Make the renderer-side prerendering code use RenderFrames instead of RenderViews.

content/public/browser/web_contents_observer.h

Index: content/public/browser/web_contents_observer.h
===================================================================
--- content/public/browser/web_contents_observer.h	(revision 239602)
+++ content/public/browser/web_contents_observer.h	(working copy)
@@ -17,6 +17,7 @@
 namespace content {
 
 class NavigationEntry;
+class RenderFrameHost;
 class RenderViewHost;
 class WebContents;
 class WebContentsImpl;
@@ -44,6 +45,13 @@
 class CONTENT_EXPORT WebContentsObserver : public IPC::Listener,
                                            public IPC::Sender {
  public:
+  // Called when a RenderFrameHost associated with this WebContents is created.
+  virtual void RenderFrameCreated(RenderFrameHost* render_frame_host) {}
+
+  // Called whenever a RenderFrameHost associated with this WebContents is
+  // deleted.
+  virtual void RenderFrameDeleted(RenderFrameHost* render_frame_host) {}
+
   // Only one of the two methods below will be called when a RVH is created for
   // a WebContents, depending on whether it's for an interstitial or not.
   virtual void RenderViewCreated(RenderViewHost* render_view_host) {}