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

ui/aura/window_tree_host.h

Index: ui/aura/window_tree_host.h
diff --git a/ui/aura/window_tree_host.h b/ui/aura/window_tree_host.h
index 03dcf1b91f1885ddf622d6f6cd69cbad9bd6d098..2c437bf42db312225aae59b292fd5c3e584b0782 100644
--- a/ui/aura/window_tree_host.h
+++ b/ui/aura/window_tree_host.h
@@ -179,6 +179,9 @@ class AURA_EXPORT WindowTreeHost : public ui::internal::InputMethodDelegate,
   // Releases OS capture of the root window.
   virtual void ReleaseCapture() = 0;
 
+  // For testing : WJM

[Charlie Reis, 2016/08/10 00:07:12]

WJM?

[wjmaclean, 2016/08/10 15:54:26]

Done.

The comment was designed to make sure I didn't leave this in ... thanks for
spotting.

+  void OnHostResized(const gfx::Size& new_size);
+
  protected:
   friend class TestScreen;  // TODO(beng): see if we can remove/consolidate.
 
@@ -193,7 +196,6 @@ class AURA_EXPORT WindowTreeHost : public ui::internal::InputMethodDelegate,
   virtual gfx::Point GetLocationOnNativeScreen() const = 0;
 
   void OnHostMoved(const gfx::Point& new_location);
-  void OnHostResized(const gfx::Size& new_size);
   void OnHostWorkspaceChanged();
   void OnHostCloseRequested();
   void OnHostActivated();