DevTools: Throttle Screencast on slow connections (Blink side)

BUG=397107

Review URL: https://codereview.chromium.org/722173003

git-svn-id: svn://svn.chromium.org/blink/trunk@185444 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/Source/devtools/front_end/screencast/ScreencastView.js

@@ -153,6 +153,9 @@ WebInspector.ScreencastView.prototype = {
         this._scrollOffsetX = metadata.scrollOffsetX;
         this._scrollOffsetY = metadata.scrollOffsetY;
 
+        if (event.data.frameNumber)
+            this._target.pageAgent().screencastFrameAck(event.data.frameNumber);
+
         var deviceSizeRatio = metadata.deviceHeight / metadata.deviceWidth;
         var dimensionsCSS = this._viewportDimensions();
 

third_party/WebKit/Source/devtools/front_end/sdk/ResourceTreeModel.js

@@ -814,10 +814,11 @@ WebInspector.PageDispatcher.prototype = {
     /**
      * @param {string} data
      * @param {!PageAgent.ScreencastFrameMetadata=} metadata
+     * @param {number=} frameNumber
      */
-    screencastFrame: function(data, metadata)
+    screencastFrame: function(data, metadata, frameNumber)
     {
-        this._resourceTreeModel.dispatchEventToListeners(WebInspector.ResourceTreeModel.EventTypes.ScreencastFrame, {data:data, metadata:metadata});
+        this._resourceTreeModel.dispatchEventToListeners(WebInspector.ResourceTreeModel.EventTypes.ScreencastFrame, {data:data, metadata:metadata, frameNumber:frameNumber});
     },
 
     /**

third_party/WebKit/Source/devtools/protocol.json

@@ -542,6 +542,15 @@
                 "hidden": true,
                 "handlers": ["browser", "renderer"]
             },
+            {
+                "name": "screencastFrameAck",
+                "description": "Acknowledges that a screencast frame has been received by the frontend.",
+                "parameters": [
+                    { "name": "frameNumber", "type": "integer", "description": "Frame number." }
+                ],
+                "hidden": true,
+                "handlers": ["browser"]
+            },
             {
                 "name": "handleJavaScriptDialog",
                 "description": "Accepts or dismisses a JavaScript initiated dialog (alert, confirm, prompt, or onbeforeunload).",
@@ -691,7 +700,8 @@
                 "description": "Compressed image data requested by the <code>startScreencast</code>.",
                 "parameters": [
                     { "name": "data", "type": "string", "description": "Base64-encoded compressed image." },
-                    { "name": "metadata", "$ref": "ScreencastFrameMetadata", "description": "Screencast frame metadata"}
+                    { "name": "metadata", "$ref": "ScreencastFrameMetadata", "description": "Screencast frame metadata."},
+                    { "name": "frameNumber", "type": "integer", "optional": true, "description": "Frame number."}
                 ],
                 "hidden": true,
                 "handlers": ["browser"]