Switch ContentSettingsObserver to be a RenderFrameObserver instead of a RenderViewObserver

chrome/browser/prerender/prerender_contents.h

Index: chrome/browser/prerender/prerender_contents.h
===================================================================
--- chrome/browser/prerender/prerender_contents.h	(revision 240362)
+++ chrome/browser/prerender/prerender_contents.h	(working copy)
@@ -5,7 +5,6 @@
 #ifndef CHROME_BROWSER_PRERENDER_PRERENDER_CONTENTS_H_
 #define CHROME_BROWSER_PRERENDER_PRERENDER_CONTENTS_H_
 
-#include <set>
 #include <string>
 #include <utility>
 #include <vector>
@@ -216,8 +215,6 @@
   // content::WebContentsObserver implementation.
   virtual void RenderFrameCreated(
       content::RenderFrameHost* render_frame_host) OVERRIDE;
-  virtual void RenderFrameDeleted(
-      content::RenderFrameHost* render_frame_host) OVERRIDE;
   virtual void DidStopLoading(
       content::RenderViewHost* render_view_host) OVERRIDE;
   virtual void DidStartProvisionalLoadForFrame(
@@ -440,9 +437,6 @@
   scoped_refptr<content::SessionStorageNamespace>
       alias_session_storage_namespace;
 
-  // The RenderFrameHosts for prerender_contents_.
-  std::set<content::RenderFrameHost*> render_frame_hosts_;
-
   DISALLOW_COPY_AND_ASSIGN(PrerenderContents);
 };