protocol.json

            },
            {
                "name": "addInspectedHeapObject",
                "parameters": [
                    { "name": "heapObjectId", "$ref": "HeapSnapshotObjectId", "description": "Heap snapshot object id to be accessible by means of $x command line API." }
                ],
                "description": "Enables console to refer to the node with given id via $x (see Command Line API for more details $x functions)."
            },
            {
                "name": "getHeapObjectId",
                "parameters": [
                    { "name": "objectId", "$ref": "Runtime.RemoteObjectId", "description": "Identifier of the object to get heap object id for." }
                ],
                "returns": [
                    { "name": "heapSnapshotObjectId", "$ref": "HeapSnapshotObjectId", "description": "Id of the heap snapshot object corresponding to the passed remote object id." }
                ]
            }
        ],
        "events": [
            {
                "name": "addHeapSnapshotChunk",
                "parameters": [
                    { "name": "chunk", "type": "string" }
                ]
            },
            {
                "name": "resetProfiles"
            },
            {
                "name": "reportHeapSnapshotProgress",
                "parameters": [
                    { "name": "done", "type": "integer" },
                    { "name": "total", "type": "integer" },
                    { "name": "finished", "type": "boolean", "optional": true }
                ]
            },
            {
                "name": "lastSeenObjectId",
                "description": "If heap objects tracking has been started then backend regulary sends a current value for last seen object id and corresponding timestamp. If the were changes in the heap since last event then one or more heapStatsUpdate events will be sent before a new lastSeenObjectId event.",
                "parameters": [
                    { "name": "lastSeenObjectId", "type": "integer" },
                    { "name": "timestamp", "type": "number" }
                ]
            },
            {
                "name": "heapStatsUpdate",
                "description": "If heap objects tracking has been started then backend may send update for one or more fragments",
                "parameters": [
                    { "name": "statsUpdate", "type": "array", "items": { "type": "integer" }, "description": "An array of triplets. Each triplet describes a fragment. The first integer is the fragment index, the second integer is a total count of objects for the fragment, the third integer is a total size of the objects for the fragment."}
                ]
            }
        ]
    },
    {
        "domain": "Worker",
        "hidden": true,
        "types": [],
        "commands": [
            {
                "name": "enable"
            },
            {
                "name": "disable"
            },
            {
                "name": "sendMessageToWorker",
                "parameters": [
                    { "name": "workerId", "type": "string" },
                    { "name": "message", "type": "string" }
                ]
            },
            {
                "name": "connectToWorker",
                "parameters": [
                    { "name": "workerId", "type": "string" }
                ]
            },
            {
                "name": "disconnectFromWorker",
                "parameters": [
                    { "name": "workerId", "type": "string" }
                ]
            },
            {
                "name": "setAutoconnectToWorkers",
                "parameters": [
                    { "name": "value", "type": "boolean" }
                ]
            }
        ],
        "events": [
            {
                "name": "workerCreated",
                "parameters": [
                    { "name": "workerId", "type": "string" },
                    { "name": "url", "type": "string" },
                    { "name": "inspectorConnected", "type": "boolean" }
                ]
            },
            {
                "name": "workerTerminated",
                "parameters": [
                    { "name": "workerId", "type": "string" }
                ]
            },
            {
                "name": "dispatchMessageFromWorker",
                "parameters": [
                    { "name": "workerId", "type": "string" },
                    { "name": "message", "type": "string" }
                ]
            }
        ]
    },
    {
        "domain": "ServiceWorker",
        "hidden": true,
        "types": [
            {
                "id": "ServiceWorkerRegistration",
                "type": "object",
                "description": "ServiceWorker registration.",
                "properties": [
                    { "name": "registrationId", "type": "string" },
                    { "name": "scopeURL", "type": "string" },
                    { "name": "isDeleted", "type": "boolean", "optional": true }
                ]
            },
            {
                "id": "ServiceWorkerVersionRunningStatus",
                "type": "string",
                "enum": ["stopped", "starting", "running", "stopping"]
            },
            {
                "id": "ServiceWorkerVersionStatus",
                "type": "string",
                "enum": ["new", "installing", "installed", "activating", "activated", "redundant"]
            },
            {
                "id": "ServiceWorkerVersion",
                "type": "object",
                "description": "ServiceWorker version.",
                "properties": [
                    { "name": "versionId", "type": "string" },
                    { "name": "registrationId", "type": "string" },
                    { "name": "scriptURL", "type": "string" },
                    { "name": "runningStatus", "$ref": "ServiceWorkerVersionRunningStatus" },
                    { "name": "status", "$ref": "ServiceWorkerVersionStatus" },
                    { "name": "scriptLastModified", "type": "number", "optional": true, "description": "The Last-Modified header value of the main script." },
                    { "name": "scriptResponseTime", "type": "number", "optional": true, "description": "The time at which the response headers of the main script were received from the server.  For cached script it is the last time the cache entry was validated." }
                ]
            },
            {
                "id": "ServiceWorkerErrorMessage",
                "type": "object",
                "description": "ServiceWorker error message.",
                "properties": [
                    { "name": "errorMessage", "type": "string" },
                    { "name": "registrationId", "type": "string" },
                    { "name": "versionId", "type": "string" },
                    { "name": "sourceURL", "type": "string" },
                    { "name": "lineNumber", "type": "integer" },
                    { "name": "columnNumber", "type": "integer" }
                ]
            }
        ],
        "commands": [
            {
                "name": "enable",
                "handlers": ["browser"]
            },
            {
                "name": "disable",
                "handlers": ["browser"]
            },
            {
                "name": "sendMessage",
                "parameters": [
                    { "name": "workerId", "type": "string" },
                    { "name": "message", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "stop",
                "parameters": [
                    { "name": "workerId", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "unregister",
                "parameters": [
                    { "name": "scopeURL", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "updateRegistration",
                "parameters": [
                    { "name": "scopeURL", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "startWorker",
                "parameters": [
                    { "name": "scopeURL", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "stopWorker",
                "parameters": [
                    { "name": "versionId", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "inspectWorker",
                "parameters": [
                    { "name": "versionId", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "setDebugOnStart",
                "parameters": [
                    { "name": "debugOnStart", "type": "boolean" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "deliverPushMessage",
                "parameters": [
                    { "name": "origin", "type": "string" },
                    { "name": "registrationId", "type": "string" },
                    { "name": "data", "type": "string" }
                ],
                "handlers": ["browser"]
            }
        ],
        "events": [
            {
                "name": "workerCreated",
                "parameters": [
                    { "name": "workerId", "type": "string" },
                    { "name": "url", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "workerTerminated",
                "parameters": [
                    { "name": "workerId", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "dispatchMessage",
                "parameters": [
                    { "name": "workerId", "type": "string" },
                    { "name": "message", "type": "string" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "workerRegistrationUpdated",
                "parameters": [
                    { "name": "registrations", "type": "array", "items": { "$ref": "ServiceWorkerRegistration" } }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "workerVersionUpdated",
                "parameters": [
                    { "name": "versions", "type": "array", "items": { "$ref": "ServiceWorkerVersion" } }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "workerErrorReported",
                "parameters": [
                    { "name": "errorMessage", "$ref": "ServiceWorkerErrorMessage" }
                ],
                "handlers": ["browser"]
            },
            {
                "name": "debugOnStartUpdated",
                "parameters": [
                    { "name": "debugOnStart", "type": "boolean" }
                ],
                "handlers": ["browser"]
            }
        ]
    },
    {
        "domain": "Canvas",
        "hidden": true,
        "types": [
            {
                "id": "ResourceId",
                "type": "string",
                "description": "Unique resource identifier."
            },
            {
                "id": "ResourceStateDescriptor",
                "type": "object",
                "description": "Resource state descriptor.",
                "properties": [
                    { "name": "name", "type": "string", "description": "State name." },
                    { "name": "enumValueForName", "type": "string", "optional": true, "description": "String representation of the enum value, if <code>name</code> stands for an enum." },
                    { "name": "value", "$ref": "CallArgument", "optional": true, "description": "The value associated with the particular state." },
                    { "name": "values", "type": "array", "items": { "$ref": "ResourceStateDescriptor" }, "optional": true, "description": "Array of values associated with the particular state. Either <code>value</code> or <code>values</code> will be specified." },
                    { "name": "isArray", "type": "boolean", "optional": true, "description": "True iff the given <code>values</code> items stand for an array rather than a list of grouped states." }
                ]
            },
            {
                "id": "ResourceState",
                "type": "object",
                "description": "Resource state.",
                "properties": [
                    { "name": "id", "$ref": "ResourceId" },
                    { "name": "traceLogId", "$ref": "TraceLogId" },
                    { "name": "descriptors", "type": "array", "items": { "$ref": "ResourceStateDescriptor" }, "optional": true, "description": "Describes current <code>Resource</code> state." },
                    { "name": "imageURL", "type": "string", "optional": true, "description": "Screenshot image data URL." }
                ]
            },
            {
                "id": "CallArgument",
                "type": "object",
                "properties": [
                    { "name": "description", "type": "string", "description": "String representation of the object." },
                    { "name": "enumName", "type": "string", "optional": true, "description": "Enum name, if any, that stands for the value (for example, a WebGL enum name)." },
                    { "name": "resourceId", "$ref": "ResourceId", "optional": true, "description": "Resource identifier. Specified for <code>Resource</code> objects only." },
                    { "name": "type", "type": "string", "optional": true, "enum": ["object", "function", "undefined", "string", "number", "boolean"], "description": "Object type. Specified for non <code>Resource</code> objects only." },
                    { "name": "subtype", "type": "string", "optional": true, "enum": ["array", "null", "node", "regexp", "date", "map", "set", "iterator", "generator", "error"], "description": "Object subtype hint. Specified for <code>object</code> type values only." },
                    { "name": "remoteObject", "$ref": "Runtime.RemoteObject", "optional": true, "description": "The <code>RemoteObject</code>, if requested." }
                ]
            },
            {
                "id": "Call",
                "type": "object",
                "properties": [
                    { "name": "contextId", "$ref": "ResourceId" },
                    { "name": "functionName", "type": "string", "optional": true },
                    { "name": "arguments", "type": "array", "items": { "$ref": "CallArgument" }, "optional": true },
                    { "name": "result", "$ref": "CallArgument", "optional": true },
                    { "name": "isDrawingCall", "type": "boolean", "optional": true },
                    { "name": "isFrameEndCall", "type": "boolean", "optional": true },
                    { "name": "property", "type": "string", "optional": true },
                    { "name": "value", "$ref": "CallArgument", "optional": true },
                    { "name": "sourceURL", "type": "string", "optional": true },
                    { "name": "lineNumber", "type": "integer", "optional": true },
                    { "name": "columnNumber", "type": "integer", "optional": true }
                ]
            },
            {
                "id": "TraceLogId",
                "type": "string",
                "description": "Unique trace log identifier."
            },
            {
                "id": "TraceLog",
                "type": "object",
                "properties": [
                    { "name": "id", "$ref": "TraceLogId" },
                    { "name": "calls", "type": "array", "items": { "$ref": "Call" } },
                    { "name": "contexts", "type": "array", "items": { "$ref": "CallArgument" } },
                    { "name": "startOffset", "type": "integer" },
                    { "name": "alive", "type": "boolean" },
                    { "name": "totalAvailableCalls", "type": "number" }
                ]
            }
        ],
        "commands": [
            {
                "name": "enable",
                "description": "Enables Canvas inspection."
            },
            {
                "name": "disable",
                "description": "Disables Canvas inspection."
            },
            {
                "name": "dropTraceLog",
                "parameters": [
                    { "name": "traceLogId", "$ref": "TraceLogId" }
                ]
            },
            {
                "name": "hasUninstrumentedCanvases",
                "returns": [
                    { "name": "result", "type": "boolean" }
                ],
                "description": "Checks if there is any uninstrumented canvas in the inspected page."
            },
            {
                "name": "captureFrame",
                "parameters": [
                    { "name": "frameId", "$ref": "Page.FrameId", "optional": true, "description": "Identifier of the frame containing document whose canvases are to be captured. If omitted, main frame is assumed." }
                ],
                "returns": [
                    { "name": "traceLogId", "$ref": "TraceLogId", "description": "Identifier of the trace log containing captured canvas calls." }
                ],
                "description": "Starts (or continues) a canvas frame capturing which will be stopped automatically after the next frame is prepared."
            },
            {
                "name": "startCapturing",
                "parameters": [
                    { "name": "frameId", "$ref": "Page.FrameId", "optional": true, "description": "Identifier of the frame containing document whose canvases are to be captured. If omitted, main frame is assumed." }
                ],
                "returns": [
                    { "name": "traceLogId", "$ref": "TraceLogId", "description": "Identifier of the trace log containing captured canvas calls." }
                ],
                "description": "Starts (or continues) consecutive canvas frames capturing. The capturing is stopped by the corresponding stopCapturing command."
            },
            {
                "name": "stopCapturing",
                "parameters": [
                    { "name": "traceLogId", "$ref": "TraceLogId" }
                ]
            },
            {
                "name": "getTraceLog",
                "parameters": [
                    { "name": "traceLogId", "$ref": "TraceLogId" },
                    { "name": "startOffset", "type": "integer", "optional": true },
                    { "name": "maxLength", "type": "integer", "optional": true }
                ],
                "returns": [
                    { "name": "traceLog", "$ref": "TraceLog" }
                ]
            },
            {
                "name": "replayTraceLog",
                "parameters": [
                    { "name": "traceLogId", "$ref": "TraceLogId" },
                    { "name": "stepNo", "type": "integer", "description": "Last call index in the trace log to replay (zero based)." }
                ],
                "returns": [
                    { "name": "resourceState", "$ref": "ResourceState" },
                    { "name": "replayTime", "type": "number", "description": "Replay time (in milliseconds)." }
                ]
            },
            {
                "name": "getResourceState",
                "parameters": [
                    { "name": "traceLogId", "$ref": "TraceLogId" },
                    { "name": "resourceId", "$ref": "ResourceId" }
                ],
                "returns": [
                    { "name": "resourceState", "$ref": "ResourceState" }
                ]
            },
            {
                "name": "evaluateTraceLogCallArgument",
                "parameters": [
                    { "name": "traceLogId", "$ref": "TraceLogId" },
                    { "name": "callIndex", "type": "integer", "description": "Index of the call to evaluate on (zero based)." },
                    { "name": "argumentIndex", "type": "integer", "description": "Index of the argument to evaluate (zero based). Provide <code>-1</code> to evaluate call result." },
                    { "name": "objectGroup", "type": "string", "optional": true, "description": "String object group name to put result into (allows rapid releasing resulting object handles using <code>Runtime.releaseObjectGroup</code>)." }
                ],
                "returns": [
                    { "name": "result", "$ref": "Runtime.RemoteObject", "optional": true, "description": "Object wrapper for the evaluation result." },
                    { "name": "resourceState", "$ref": "ResourceState", "optional": true, "description": "State of the <code>Resource</code> object." }
                ],
                "description": "Evaluates a given trace call argument or its result."
            }
        ],
        "events": [
            {
                "name": "contextCreated",
                "parameters": [
                    { "name": "frameId", "$ref": "Page.FrameId", "description": "Identifier of the frame containing a canvas with a context." }
                ],
                "description": "Fired when a canvas context has been created in the given frame. The context may not be instrumented (see hasUninstrumentedCanvases command)."
            },
            {
                "name": "traceLogsRemoved",
                "parameters": [
                    { "name": "frameId", "$ref": "Page.FrameId", "optional": true, "description": "If given, trace logs from the given frame were removed." },
                    { "name": "traceLogId", "$ref": "TraceLogId", "optional": true, "description": "If given, trace log with the given ID was removed." }
                ],
                "description": "Fired when a set of trace logs were removed from the backend. If no parameters are given, all trace logs were removed."
            }
        ]
    },
    {
        "domain": "Input",
        "types": [
            {
                "id": "TouchPoint",
                "type": "object",
                "hidden": true,
                "properties": [
                    { "name": "state", "type": "string", "enum": ["touchPressed", "touchReleased", "touchMoved", "touchStationary", "touchCancelled"], "description": "State of the touch point." },
                    { "name": "x", "type": "integer", "description": "X coordinate of the event relative to the main frame's viewport."},
                    { "name": "y", "type": "integer", "description": "Y coordinate of the event relative to the main frame's viewport. 0 refers to the top of the viewport and Y increases as it proceeds towards the bottom of the viewport."},
                    { "name": "radiusX", "type": "integer", "optional": true, "description": "X radius of the touch area (default: 1)."},
                    { "name": "radiusY", "type": "integer", "optional": true, "description": "Y radius of the touch area (default: 1)."},
                    { "name": "rotationAngle", "type": "number", "optional": true, "description": "Rotation angle (default: 0.0)."},
                    { "name": "force", "type": "number", "optional": true, "description": "Force (default: 1.0)."},
                    { "name": "id", "type": "number", "optional": true, "description": "Identifier used to track touch sources between events, must be unique within an event."}
                ]
            },
            {
                "id": "GestureSourceType",
                "type": "string",
                "hidden": true,
                "enum": ["default", "touch", "mouse"]
            }
        ],
        "commands": [
            {
                "name": "dispatchKeyEvent",
                "parameters": [
                    { "name": "type", "type": "string", "enum": ["keyDown", "keyUp", "rawKeyDown", "char"], "description": "Type of the key event." },
                    { "name": "modifiers", "type": "integer", "optional": true, "description": "Bit field representing pressed modifier keys. Alt=1, Ctrl=2, Meta/Command=4, Shift=8 (default: 0)." },
                    { "name": "timestamp", "type": "number", "optional": true, "description": "Time at which the event occurred. Measured in UTC time in seconds since January 1, 1970 (default: current time)." },
                    { "name": "text", "type": "string", "optional": true, "description": "Text as generated by processing a virtual key code with a keyboard layout. Not needed for for <code>keyUp</code> and <code>rawKeyDown</code> events (default: \"\")" },
                    { "name": "unmodifiedText", "type": "string", "optional": true, "description": "Text that would have been generated by the keyboard if no modifiers were pressed (except for shift). Useful for shortcut (accelerator) key handling (default: \"\")." },
                    { "name": "keyIdentifier", "type": "string", "optional": true, "description": "Unique key identifier (e.g., 'U+0041') (default: \"\")." },
                    { "name": "code", "type": "string", "optional": true, "description": "Unique DOM defined string value for each physical key (e.g., 'KeyA') (default: \"\")." },
                    { "name": "windowsVirtualKeyCode", "type": "integer", "optional": true, "description": "Windows virtual key code (default: 0)." },
                    { "name": "nativeVirtualKeyCode", "type": "integer", "optional": true, "description": "Native virtual key code (default: 0)." },
                    { "name": "autoRepeat", "type": "boolean", "optional": true, "description": "Whether the event was generated from auto repeat (default: false)." },
                    { "name": "isKeypad", "type": "boolean", "optional": true, "description": "Whether the event was generated from the keypad (default: false)." },
                    { "name": "isSystemKey", "type": "boolean", "optional": true, "description": "Whether the event was a system key event (default: false)." }
                ],
                "description": "Dispatches a key event to the page.",
                "handlers": ["browser"]
            },
            {
                "name": "dispatchMouseEvent",
                "parameters": [
                    { "name": "type", "type": "string", "enum": ["mousePressed", "mouseReleased", "mouseMoved"], "description": "Type of the mouse event." },
                    { "name": "x", "type": "integer", "description": "X coordinate of the event relative to the main frame's viewport."},
                    { "name": "y", "type": "integer", "description": "Y coordinate of the event relative to the main frame's viewport. 0 refers to the top of the viewport and Y increases as it proceeds towards the bottom of the viewport."},
                    { "name": "modifiers", "type": "integer", "optional": true, "description": "Bit field representing pressed modifier keys. Alt=1, Ctrl=2, Meta/Command=4, Shift=8 (default: 0)." },
                    { "name": "timestamp", "type": "number", "optional": true, "description": "Time at which the event occurred. Measured in UTC time in seconds since January 1, 1970 (default: current time)." },
                    { "name": "button", "type": "string", "enum": ["none", "left", "middle", "right"], "optional": true, "description": "Mouse button (default: \"none\")." },
                    { "name": "clickCount", "type": "integer", "optional": true, "description": "Number of times the mouse button was clicked (default: 0)." }
                ],
                "description": "Dispatches a mouse event to the page.",
                "handlers": ["browser"]
            },
            {
                "name": "dispatchTouchEvent",
                "hidden": true,
                "parameters": [
                    { "name": "type", "type": "string", "enum": ["touchStart", "touchEnd", "touchMove"], "description": "Type of the touch event." },
                    { "name": "touchPoints", "type": "array", "items": { "$ref": "TouchPoint" }, "description": "Touch points." },
                    { "name": "modifiers", "type": "integer", "optional": true, "description": "Bit field representing pressed modifier keys. Alt=1, Ctrl=2, Meta/Command=4, Shift=8 (default: 0)." },
                    { "name": "timestamp", "type": "number", "optional": true, "description": "Time at which the event occurred. Measured in UTC time in seconds since January 1, 1970 (default: current time)." }
                ],
                "description": "Dispatches a touch event to the page."
            },
            {
                "name": "emulateTouchFromMouseEvent",
                "hidden": true,
                "parameters": [
                    { "name": "type", "type": "string", "enum": ["mousePressed", "mouseReleased", "mouseMoved", "mouseWheel"], "description": "Type of the mouse event." },
                    { "name": "x", "type": "integer", "description": "X coordinate of the mouse pointer in DIP."},
                    { "name": "y", "type": "integer", "description": "Y coordinate of the mouse pointer in DIP."},
                    { "name": "timestamp", "type": "number", "description": "Time at which the event occurred. Measured in UTC time in seconds since January 1, 1970." },
                    { "name": "button", "type": "string", "enum": ["none", "left", "middle", "right"], "description": "Mouse button." },
                    { "name": "deltaX", "type": "number", "optional": true, "description": "X delta in DIP for mouse wheel event (default: 0)."},
                    { "name": "deltaY", "type": "number", "optional": true, "description": "Y delta in DIP for mouse wheel event (default: 0)."},
                    { "name": "modifiers", "type": "integer", "optional": true, "description": "Bit field representing pressed modifier keys. Alt=1, Ctrl=2, Meta/Command=4, Shift=8 (default: 0)." },
                    { "name": "clickCount", "type": "integer", "optional": true, "description": "Number of times the mouse button was clicked (default: 0)." }
                ],
                "description": "Emulates touch event from the mouse event parameters.",
                "handlers": ["browser"]
            },
            {
                "name": "synthesizePinchGesture",
                "async": true,
                "parameters": [
                    { "name": "x", "type": "integer", "description": "X coordinate of the start of the gesture in CSS pixels." },
                    { "name": "y", "type": "integer", "description": "Y coordinate of the start of the gesture in CSS pixels." },
                    { "name": "scaleFactor", "type": "number", "description": "Relative scale factor after zooming (>1.0 zooms in, <1.0 zooms out)." },
                    { "name": "relativeSpeed", "type": "integer", "optional": true, "description": "Relative pointer speed in pixels per second (default: 800)." },
                    { "name": "gestureSourceType", "$ref": "GestureSourceType", "optional": true, "description": "Which type of input events to be generated (default: 'default', which queries the platform for the preferred input type)." }
                ],
                "description": "Synthesizes a pinch gesture over a time period by issuing appropriate touch events.",
                "hidden": true,
                "handlers": ["browser"]
            },
            {
                "name": "synthesizeScrollGesture",
                "async": true,
                "parameters": [
                    { "name": "x", "type": "integer", "description": "X coordinate of the start of the gesture in CSS pixels." },
                    { "name": "y", "type": "integer", "description": "Y coordinate of the start of the gesture in CSS pixels." },
                    { "name": "xDistance", "type": "integer", "optional": true, "description": "The distance to scroll along the X axis (positive to scroll left)." },
                    { "name": "yDistance", "type": "integer", "optional": true, "description": "The distance to scroll along the Y axis (positive to scroll up)." },
                    { "name": "xOverscroll", "type": "integer", "optional": true, "description": "The number of additional pixels to scroll back along the X axis, in addition to the given distance." },
                    { "name": "yOverscroll", "type": "integer", "optional": true, "description": "The number of additional pixels to scroll back along the Y axis, in addition to the given distance." },
                    { "name": "preventFling", "type": "boolean", "optional": true, "description": "Prevent fling (default: true)." },
                    { "name": "speed", "type": "integer", "optional": true, "description": "Swipe speed in pixels per second (default: 800)." },
                    { "name": "gestureSourceType", "$ref": "GestureSourceType", "optional": true, "description": "Which type of input events to be generated (default: 'default', which queries the platform for the preferred input type)." }
                ],
                "description": "Synthesizes a scroll gesture over a time period by issuing appropriate touch events.",
                "hidden": true,
                "handlers": ["browser"]
            },
            {
                "name": "synthesizeTapGesture",
                "async": true,
                "parameters": [
                    { "name": "x", "type": "integer", "description": "X coordinate of the start of the gesture in CSS pixels." },
                    { "name": "y", "type": "integer", "description": "Y coordinate of the start of the gesture in CSS pixels." },
                    { "name": "duration", "type": "integer", "optional": true, "description": "Duration between touchdown and touchup events in ms (default: 50)." },
                    { "name": "tapCount", "type": "integer", "optional": true, "description": "Number of times to perform the tap (e.g. 2 for double tap, default: 1)." },
                    { "name": "gestureSourceType", "$ref": "GestureSourceType", "optional": true, "description": "Which type of input events to be generated (default: 'default', which queries the platform for the preferred input type)." }
                ],
                "description": "Synthesizes a tap gesture over a time period by issuing appropriate touch events.",
                "hidden": true,
                "handlers": ["browser"]
            }
        ],
        "events": []
    },
    {
        "domain": "LayerTree",
        "hidden": true,
        "types": [
            {
                "id": "LayerId",
                "type": "string",
                "description": "Unique Layer identifier."
            },
            {
                "id": "SnapshotId",
                "type": "string",
                "description": "Unique snapshot identifier."
            },
            {
                "id": "ScrollRect",
                "type": "object",
                "description": "Rectangle where scrolling happens on the main thread.",
                "properties": [
                    { "name": "rect", "$ref": "DOM.Rect", "description": "Rectangle itself." },
                    { "name": "type", "type": "string", "enum": ["RepaintsOnScroll", "TouchEventHandler", "WheelEventHandler"], "description": "Reason for rectangle to force scrolling on the main thread" }
                ]
            },
            {
                "id": "PictureTile",
                "type": "object",
                "description": "Serialized fragment of layer picture along with its offset within the layer.",
                "properties": [
                    { "name": "x", "type": "number", "description": "Offset from owning layer left boundary" },
                    { "name": "y", "type": "number", "description": "Offset from owning layer top boundary" },
                    { "name": "picture", "type": "string", "description": "Base64-encoded snapshot data." }
                ]
            },
            {
                "id": "Layer",
                "type": "object",
                "description": "Information about a compositing layer.",
                "properties": [
                    { "name": "layerId", "$ref": "LayerId", "description": "The unique id for this layer." },
                    { "name": "parentLayerId", "$ref": "LayerId", "optional": true, "description": "The id of parent (not present for root)." },
                    { "name": "backendNodeId", "$ref": "DOM.BackendNodeId", "optional": true, "description": "The backend id for the node associated with this layer." },
                    { "name": "offsetX", "type": "number", "description": "Offset from parent layer, X coordinate." },
                    { "name": "offsetY", "type": "number", "description": "Offset from parent layer, Y coordinate." },
                    { "name": "width", "type": "number", "description": "Layer width." },
                    { "name": "height", "type": "number", "description": "Layer height." },
                    { "name": "transform", "type": "array", "items": { "type": "number" }, "minItems": 16, "maxItems": 16, "optional": true, "description": "Transformation matrix for layer, default is identity matrix" },
                    { "name": "anchorX", "type": "number", "optional": true, "description": "Transform anchor point X, absent if no transform specified" },
                    { "name": "anchorY", "type": "number", "optional": true, "description": "Transform anchor point Y, absent if no transform specified" },
                    { "name": "anchorZ", "type": "number", "optional": true, "description": "Transform anchor point Z, absent if no transform specified" },
                    { "name": "paintCount", "type": "integer", "description": "Indicates how many time this layer has painted." },
                    { "name": "drawsContent", "type": "boolean", "description": "Indicates whether this layer hosts any content, rather than being used for transform/scrolling purposes only." },
                    { "name": "invisible", "type": "boolean", "optional": true, "description": "Set if layer is not visible." },
                    { "name": "scrollRects", "type": "array", "items": { "$ref": "ScrollRect"}, "optional": true, "description": "Rectangles scrolling on main thread only."}
                ]
            },
            {
                "id": "PaintProfile",
                "type": "array",
                "description": "Array of timings, one per paint step.",
                "items": {
                    "type": "number",
                    "description": "A time in seconds since the end of previous step (for the first step, time since painting started)"
                }
            }
        ],
        "commands": [
            {
                "name": "enable",
                "description": "Enables compositing tree inspection."
            },
            {
                "name": "disable",
                "description": "Disables compositing tree inspection."
            },
            {
                "name": "compositingReasons",
                "parameters": [
                    { "name": "layerId", "$ref": "LayerId", "description": "The id of the layer for which we want to get the reasons it was composited." }
                ],
                "description": "Provides the reasons why the given layer was composited.",
                "returns": [
                    { "name": "compositingReasons", "type": "array", "items": { "type": "string" }, "description": "A list of strings specifying reasons for the given layer to become composited." }
                ]
            },
            {
                "name": "makeSnapshot",
                "parameters": [
                    { "name": "layerId", "$ref": "LayerId", "description": "The id of the layer." }
                ],
                "description": "Returns the layer snapshot identifier.",
                "returns": [
                    { "name": "snapshotId", "$ref": "SnapshotId", "description": "The id of the layer snapshot." }
                ]
            },
            {
                "name": "loadSnapshot",
                "parameters": [
                    { "name": "tiles", "type": "array", "items": { "$ref": "PictureTile" }, "minItems": 1, "description": "An array of tiles composing the snapshot." }
                ],
                "description": "Returns the snapshot identifier.",
                "returns": [
                    { "name": "snapshotId", "$ref": "SnapshotId", "description": "The id of the snapshot." }
                ]
            },
            {
                "name": "releaseSnapshot",
                "parameters": [
                    { "name": "snapshotId", "$ref": "SnapshotId", "description": "The id of the layer snapshot." }
                ],
                "description": "Releases layer snapshot captured by the back-end."
            },
            {
                "name": "profileSnapshot",
                "parameters": [
                    { "name": "snapshotId", "$ref": "SnapshotId", "description": "The id of the layer snapshot." },
                    { "name": "minRepeatCount", "type": "integer", "optional": true, "description": "The maximum number of times to replay the snapshot (1, if not specified)." },
                    { "name": "minDuration", "type": "number", "optional": true, "description": "The minimum duration (in seconds) to replay the snapshot." },
                    { "name": "clipRect", "$ref": "DOM.Rect", "optional": true, "description": "The clip rectangle to apply when replaying the snapshot." }
                ],
                "returns": [
                    { "name": "timings", "type": "array", "items": { "$ref": "PaintProfile" }, "description": "The array of paint profiles, one per run." }
                ]
            },
            {
                "name": "replaySnapshot",
                "parameters": [
                    { "name": "snapshotId", "$ref": "SnapshotId", "description": "The id of the layer snapshot." },
                    { "name": "fromStep", "type": "integer", "optional": true, "description": "The first step to replay from (replay from the very start if not specified)." },
                    { "name": "toStep", "type": "integer", "optional": true, "description": "The last step to replay to (replay till the end if not specified)." },
                    { "name": "scale", "type": "number", "optional": true, "description": "The scale to apply while replaying (defaults to 1)." }
                ],
                "description": "Replays the layer snapshot and returns the resulting bitmap.",
                "returns": [
                    { "name": "dataURL", "type": "string", "description": "A data: URL for resulting image." }
                ]
            },
            {
                "name": "snapshotCommandLog",
                "parameters": [
                    { "name": "snapshotId", "$ref": "SnapshotId", "description": "The id of the layer snapshot." }
                ],
                "description": "Replays the layer snapshot and returns canvas log.",
                "returns": [
                    { "name": "commandLog", "type": "array", "items": { "type": "object" }, "description": "The array of canvas function calls." }
                ]
            }
        ],
        "events": [
            {
                "name": "layerTreeDidChange",
                "parameters": [
                    { "name": "layers", "type": "array", "items": { "$ref": "Layer" }, "optional": true, "description": "Layer tree, absent if not in the comspositing mode." }
                ]
            },
            {
                "name": "layerPainted",
                "parameters": [
                    { "name": "layerId", "$ref": "LayerId", "description": "The id of the painted layer." },
                    { "name": "clip", "$ref": "DOM.Rect", "description": "Clip rectangle." }
                ]
            }
        ]
    },
    {
        "domain": "DeviceOrientation",
        "hidden": true,
        "commands": [
            {
                "name": "setDeviceOrientationOverride",
                "description": "Overrides the Device Orientation.",
                "parameters": [
                    { "name": "alpha", "type": "number", "description": "Mock alpha"},
                    { "name": "beta", "type": "number", "description": "Mock beta"},
                    { "name": "gamma", "type": "number", "description": "Mock gamma"}
                ]
            },
            {
                "name": "clearDeviceOrientationOverride",
                "description": "Clears the overridden Device Orientation."
            }
        ]
    },
    {
        "domain": "Tracing",
        "commands": [
            {
                "name": "start",
                "async": true,
                "description": "Start trace events collection.",
                "parameters": [
                    { "name": "categories", "type": "string", "optional": true, "description": "Category/tag filter" },
                    { "name": "options", "type": "string", "optional": true, "description": "Tracing options" },
                    { "name": "bufferUsageReportingInterval", "type": "number", "optional": true, "description": "If set, the agent will issue bufferUsage events at this interval, specified in milliseconds" }
                ],
                "handlers": ["browser", "renderer"]
            },
            {
                "name": "end",
                "async": true,
                "description": "Stop trace events collection.",
                "handlers": ["browser", "renderer"]
            },
            {
                "name": "getCategories",
                "async": true,
                "description": "Gets supported tracing categories.",
                "returns": [
                    { "name": "categories", "type": "array", "items": { "type": "string" }, "description": "A list of supported tracing categories." }
                ],
                "handlers": ["browser"]
            }
        ],
        "events": [
            {
                "name": "dataCollected",
                "parameters": [
                    { "name": "value", "type": "array", "items": { "type": "object" } }
                ],
                "description": "Contains an bucket of collected trace events. When tracing is stopped collected events will be send as a sequence of dataCollected events followed by tracingComplete event.",
                "handlers": ["browser"]
            },
            {
                "name": "tracingComplete",
                "description": "Signals that tracing is stopped and there is no trace buffers pending flush, all data were delivered via dataCollected events.",
                "handlers": ["browser"]
            },
            {
                "name": "bufferUsage",
                "parameters": [
                    { "name": "percentFull", "type": "number", "optional": true, "description": "A number in range [0..1] that indicates the used size of event buffer as a fraction of its total size." },
                    { "name": "eventCount", "type": "number", "optional": true, "description": "An approximate number of events in the trace log." },
                    { "name": "value", "type": "number", "optional": true, "description": "A number in range [0..1] that indicates the used size of event buffer as a fraction of its total size." }
                ],
                "handlers": ["browser"]
            }
        ]
    },
    {
        "domain": "Power",
        "hidden": true,
        "types": [
            {
                "id": "PowerEvent",
                "type": "object",
                "properties": [
                    { "name": "type", "type": "string", "description": "Power Event Type." },
                    { "name": "timestamp", "type": "number", "description": "Power Event Time, in milliseconds." },
                    { "name": "value", "type": "number", "description": "Power Event Value." }
                ],
            "description": "PowerEvent item"
            }
        ],
        "commands": [
            {
                "name": "start",
                "description": "Start power events collection.",
                "parameters": [],
                "handlers": ["browser", "frontend"]
            },
            {
                "name": "end",
                "description": "Stop power events collection.",
                "parameters": [],
                "handlers": ["browser", "frontend"]
            },
            {
                "name": "canProfilePower",
                "description": "Tells whether power profiling is supported.",
                "returns": [
                  { "name": "result", "type": "boolean", "description": "True if power profiling is supported." }
                ],
                "hidden": true,
                "handlers": ["browser", "frontend"]
            },
            {
                "name": "getAccuracyLevel",
                "description": "Describes the accuracy level of the data provider.",
                "returns": [
                    { "name": "result", "type": "string", "enum": ["high", "moderate", "low"] }
                ],
                "handlers": ["browser", "frontend"]
            }
        ],
        "events": [
            {
                "name": "dataAvailable",
                "parameters": [
                    {"name": "value", "type": "array", "items": { "$ref": "PowerEvent" }, "description": "List of power events." }
                ],
                "handlers": ["browser", "frontend"]
            }
        ]
    },
    {
        "domain": "Animation",
        "hidden": true,
        "types": [
            {
                "id": "AnimationPlayer",
                "type": "object",
                "hidden": true,
                "properties": [
                    { "name": "id", "type": "string", "description": "<code>AnimationPlayer</code>'s id." },
                    { "name": "pausedState", "type": "boolean", "hidden": "true", "description": "<code>AnimationPlayer</code>'s internal paused state." },
                    { "name": "playState", "type": "string", "description": "<code>AnimationPlayer</code>'s play state." },
                    { "name": "playbackRate", "type": "number", "description": "<code>AnimationPlayer</code>'s playback rate." },
                    { "name": "startTime", "type": "number", "description": "<code>AnimationPlayer</code>'s start time." },
                    { "name": "currentTime", "type": "number", "description": "<code>AnimationPlayer</code>'s current time." },
                    { "name": "source", "$ref": "AnimationNode", "description": "<code>AnimationPlayer</code>'s source animation node." },
                    { "name": "type", "type": "string", "enum": ["CSSTransition", "CSSAnimation", "WebAnimation"], "description": "Animation type of <code>AnimationPlayer</code>." }
                ],
                "description": "AnimationPlayer instance."
            },
            {
                "id": "AnimationNode",
                "type": "object",
                "hidden": true,
                "properties": [
                    { "name": "delay", "type": "number", "description": "<code>AnimationNode</code>'s delay." },
                    { "name": "endDelay", "type": "number", "description": "<code>AnimationNode</code>'s end delay." },
                    { "name": "playbackRate", "type": "number", "description": "<code>AnimationNode</code>'s playbackRate." },
                    { "name": "iterationStart", "type": "number", "description": "<code>AnimationNode</code>'s iteration start." },
                    { "name": "iterations", "type": "number", "description": "<code>AnimationNode</code>'s iterations." },
                    { "name": "duration", "type": "number", "description": "<code>AnimationNode</code>'s iteration duration." },
                    { "name": "direction", "type": "string", "description": "<code>AnimationNode</code>'s playback direction." },
                    { "name": "fill", "type": "string", "description": "<code>AnimationNode</code>'s fill mode." },
                    { "name": "name", "type": "string", "description": "<code>AnimationNode</code>'s name." },
                    { "name": "backendNodeId", "$ref": "DOM.BackendNodeId", "description": "<code>AnimationNode</code>'s target node." },
                    { "name": "keyframesRule", "$ref": "KeyframesRule", "optional": true, "description": "<code>AnimationNode</code>'s keyframes." },
                    { "name": "easing", "type": "string", "description": "<code>AnimationNode</code>'s timing function." }
                ],
                "description": "AnimationNode instance"
            },
            {
                "id": "KeyframesRule",
                "type": "object",
                "properties": [
                    { "name": "name", "type": "string", "optional": true, "description": "CSS keyframed animation's name." },
                    { "name": "keyframes", "type": "array", "items": { "$ref": "KeyframeStyle" }, "description": "List of animation keyframes." }
                ],
                "description": "Keyframes Rule"
            },
            {
                "id": "KeyframeStyle",
                "type": "object",
                "properties": [
                    { "name": "offset", "type": "string", "description": "Keyframe's time offset." },
                    { "name": "easing", "type": "string", "description": "<code>AnimationNode</code>'s timing function." }
                ],
                "description": "Keyframe Style"
            }
        ],
        "commands": [
            {
                "name": "enable",
                "description": "Enables animation domain notifications."
            },
            {
                "name": "getAnimationPlayersForNode",
                "parameters": [
                    { "name": "nodeId", "$ref": "DOM.NodeId", "description": "Id of the node to get animation players for." },
                    { "name": "includeSubtreeAnimations", "type": "boolean", "description": "Include animations from elements subtree." }
                ],
                "returns": [
                    { "name": "animationPlayers", "type": "array", "items": { "$ref": "AnimationPlayer" }, "description": "Array of animation players." }
                ],
                "description": "Returns animation players relevant to the node.",
                "hidden": true
            },
            {
                "name": "getPlaybackRate",
                "returns": [
                    { "name": "playbackRate", "type": "number", "description": "Playback rate for animations on page."}
                ],
                "description": "Gets the playback rate of the document timeline."
            },