[Devtools] Fixes screencast when devtools is screencasting

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 109 matching lines @@
     this._isCasting = true;
 
     const maxImageDimension = 2048;
     var dimensions = this._viewportDimensions();
     if (dimensions.width < 0 || dimensions.height < 0) {
       this._isCasting = false;
       return;
     }
     dimensions.width *= window.devicePixelRatio;
     dimensions.height *= window.devicePixelRatio;
+    // Note: startScreencast with and height expect to be integers so must be floored.
     this._target.pageAgent().startScreencast(
-        'jpeg', 80, Math.min(maxImageDimension, dimensions.width), Math.min(maxImageDimension, dimensions.height));
+        'jpeg', 80, Math.floor(Math.min(maxImageDimension, dimensions.width)),
+        Math.floor(Math.min(maxImageDimension, dimensions.height)));
     this._target.emulationAgent().setTouchEmulationEnabled(true);
     this._domModel.setHighlighter(this);
   }
 
   _stopCasting() {
     if (!this._isCasting)
       return;
     this._isCasting = false;
     this._target.pageAgent().stopScreencast();
     this._target.emulationAgent().setTouchEmulationEnabled(false);
@@ skipping 721 matching lines @@
     if (this._maxDisplayedProgress >= progress)
       return;
     this._maxDisplayedProgress = progress;
     this._displayProgress(progress);
   }
 
   _displayProgress(progress) {
     this._element.style.width = (100 * progress) + '%';
   }
 };