Introduce painted-device-scale-factor and use it when --enable-use-zoom-for-dsf is specified.

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index de967c460f0b6e703ee7d6941f9cd5d5137b6d67..dd688a0210a587b7ee6c6d5760423164bfb8cfe1 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -571,6 +571,11 @@ class CONTENT_EXPORT RenderWidget
   scoped_ptr<WebGraphicsContext3DCommandBufferImpl> CreateGraphicsContext3D(
       bool compositor);
 
+  // Sets the size of the compositor's viewport to the latest size.
+  //

[danakj, 2015/10/22 23:15:29]

extra lines?

[oshima, 2015/10/23 18:05:37]

Done.

+  //
+  void UpdateCompositorViewportSize();
+
   // Routing ID that allows us to communicate to the parent browser process
   // RenderWidgetHost. When MSG_ROUTING_NONE, no messages may be sent.
   int32 routing_id_;