For OSX, make it so that notifications only start resizing after the first paint is done.

chrome/browser/notifications/balloon_host.h

Index: chrome/browser/notifications/balloon_host.h
diff --git a/chrome/browser/notifications/balloon_host.h b/chrome/browser/notifications/balloon_host.h
index 4e51eba1752154a09a4c774b370d89ebb7bcc1d3..c5a88e760c6df3c4677576a7ccf63fa339460823 100644
--- a/chrome/browser/notifications/balloon_host.h
+++ b/chrome/browser/notifications/balloon_host.h
@@ -112,6 +112,9 @@ class BalloonHost : public RenderViewHostDelegate,
                                       const std::string& value);
   virtual void ClearInspectorSettings();
 
+  // Called when the render view has painted.
+  void RenderWidgetHostDidPaint();
+
  protected:
   virtual ~BalloonHost();
   // Must override in platform specific implementations.