Refactor ExtensionView to support a UI-less extension instance....

chrome/browser/renderer_host/render_widget_host.h

Index: chrome/browser/renderer_host/render_widget_host.h
===================================================================
--- chrome/browser/renderer_host/render_widget_host.h	(revision 14851)
+++ chrome/browser/renderer_host/render_widget_host.h	(working copy)
@@ -8,6 +8,7 @@
 #include <queue>
 #include <vector>
 
+#include "base/gfx/native_widget_types.h"
 #include "base/gfx/size.h"
 #include "base/scoped_ptr.h"
 #include "base/timer.h"
@@ -267,6 +268,9 @@
   // consistent if a new renderer is created.
   void RendererExited();
 
+  // Retrieves the native view used to contain plugins.
+  gfx::NativeViewId GetPluginNativeViewId();
+
   // Called when we an InputEvent was not processed by the renderer. This is
   // overridden by RenderView to send upwards to its delegate.
   virtual void UnhandledKeyboardEvent(const NativeWebKeyboardEvent& event) {}