Cross-process frames should be notified of device scale factor changes.

content/browser/renderer_host/render_widget_host_delegate.h

Index: content/browser/renderer_host/render_widget_host_delegate.h
diff --git a/content/browser/renderer_host/render_widget_host_delegate.h b/content/browser/renderer_host/render_widget_host_delegate.h
index 1aab2bb6d941db12e3dc296067d131a0d77b7276..0ac9aa600af0e54319b2a1157eea36e0a4ccf5fd 100644
--- a/content/browser/renderer_host/render_widget_host_delegate.h
+++ b/content/browser/renderer_host/render_widget_host_delegate.h
@@ -18,6 +18,7 @@
 namespace blink {
 class WebMouseWheelEvent;
 class WebGestureEvent;
+struct WebScreenInfo;
 }
 
 namespace gfx {
@@ -61,6 +62,12 @@ class CONTENT_EXPORT RenderWidgetHostDelegate {
   // The screen info has changed.
   virtual void ScreenInfoChanged() {}
 
+  // Sets the device scale factor for frames associated with this WebContents.
+  virtual void UpdateDeviceScaleFactor(double device_scale_factor) {}
+
+  // Retrieve screen information.
+  virtual void GetScreenInfo(blink::WebScreenInfo* web_screen_info);
+
   // Callback to give the browser a chance to handle the specified keyboard
   // event before sending it to the renderer.
   // Returns true if the |event| was handled. Otherwise, if the |event| would