Defer CGLFlushDrawable until OSX-requested drawRect to avoid spinning when window is obscured.

content/port/browser/render_widget_host_view_port.h

Index: content/port/browser/render_widget_host_view_port.h
diff --git a/content/port/browser/render_widget_host_view_port.h b/content/port/browser/render_widget_host_view_port.h
index 8ff0c5d5908a00d196041de8d46d1e8452aefdee..06a58ac389784d69938edf1a2bdcf9830f29cef9 100644
--- a/content/port/browser/render_widget_host_view_port.h
+++ b/content/port/browser/render_widget_host_view_port.h
@@ -176,6 +176,9 @@ class CONTENT_EXPORT RenderWidgetHostViewPort : public RenderWidgetHostView {
   // returned only if the accelerated surface size matches.
   virtual bool HasAcceleratedSurface(const gfx::Size& desired_size) = 0;
 
+  // Called just before GetBackingStore blocks for an updated frame.
+  virtual void AboutToWaitForBackingStoreMsg() {}

[Jói, 2012/05/18 07:28:27]

I'd prefer to leave this pure virtual like all the other methods.  Should this
be within the #if defined(OS_MACOSX) block since you only implement it for Mac?

[jbates, 2012/05/21 22:41:59]

Done.

+
 #if defined(OS_MACOSX)
   // Retrieve the bounds of the view, in cocoa view coordinates.
   // If the UI scale factor is 2, |GetViewBounds()| will return a size of e.g.