Adds DevTools commands for forced viewport override.

third_party/WebKit/public/platform/WebLayerTreeView.h

 /*
  * Copyright (C) 2011 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 49 matching lines @@
     virtual void setRootLayer(const WebLayer&) { }
     virtual void clearRootLayer() { }
 
     // TODO(loyso): These should use CompositorAnimationTimeline. crbug.com/584551
     virtual void attachCompositorAnimationTimeline(cc::AnimationTimeline*) { }
     virtual void detachCompositorAnimationTimeline(cc::AnimationTimeline*) { }
 
     // View properties ---------------------------------------------------
 
     virtual void setViewportSize(const WebSize& deviceViewportSize) { }
+    virtual WebSize getViewportSize() const { return WebSize(); }

[chrishtr, 2016/08/22 22:00:42]

In what coordinate space? Not including the device scale factor?

[Eric Seckler, 2016/08/23 09:32:19]

It's in physical pixels. Added a comment.

 
     virtual void setDeviceScaleFactor(float) { }
+    virtual float getDeviceScaleFactor() const { return 1.f; }

[dgozman, 2016/08/22 22:22:06]

Having both set and get here looks strange. AFAIU, blink is supposed to control
WebLayerTreeView so it should already know the device scale factor it set.

[Eric Seckler, 2016/08/23 09:32:19]

True, except that there could be a device_scale_factor override in place within
Blink, which is why I query it from the layerTreeView/compositor. I got rid of
this and instead added a compositorDeviceScaleFactor() accessor to WebViewImpl
that returns |m_compositorDeviceScaleFactorOverride| if an override is active.
Is that more appropriate?

 
     // Sets the background color for the viewport.
     virtual void setBackgroundColor(WebColor) { }
 
     // Sets the background transparency for the viewport. The default is 'false'.
     virtual void setHasTransparentBackground(bool) { }
 
     // Sets whether this view is visible. In threaded mode, a view that is not visible will not
     // composite or trigger updateAnimations() or layout() calls until it becomes visible.
     virtual void setVisible(bool) { }
@@ skipping 85 matching lines @@
     // Toggles the debug borders on layers
     virtual void setShowDebugBorders(bool) { }
 
     // Toggles scroll bottleneck rects on the HUD layer
     virtual void setShowScrollBottleneckRects(bool) { }
 };
 
 } // namespace blink
 
 #endif // WebLayerTreeView_h