Switch ContentSettingsObserver to be a RenderFrameObserver instead of a RenderViewObserver

chrome/browser/prerender/prerender_contents.cc

Index: chrome/browser/prerender/prerender_contents.cc
===================================================================
--- chrome/browser/prerender/prerender_contents.cc	(revision 241294)
+++ chrome/browser/prerender/prerender_contents.cc	(working copy)
@@ -163,11 +163,10 @@
 }
 
 void PrerenderContents::PrepareForUse() {
-  for (std::set<content::RenderFrameHost*>::iterator i =
-           render_frame_hosts_.begin(); i != render_frame_hosts_.end(); ++i) {
-    (*i)->Send(new PrerenderMsg_SetIsPrerendering((*i)->GetRoutingID(), false));
+  if (prerender_contents_.get()) {
+    prerender_contents_->SendToAllFrames(
+        new PrerenderMsg_SetIsPrerendering(MSG_ROUTING_NONE, false));
   }
-  render_frame_hosts_.clear();
 
   NotifyPrerenderStop();
 
@@ -547,7 +546,6 @@
 
 void PrerenderContents::RenderFrameCreated(
     content::RenderFrameHost* render_frame_host) {
-  render_frame_hosts_.insert(render_frame_host);
   // When a new RenderFrame is created for a prerendering WebContents, tell the
   // new RenderFrame it's being used for prerendering before any navigations
   // occur.  Note that this is always triggered before the first navigation, so
@@ -556,11 +554,6 @@
       render_frame_host->GetRoutingID(), true));
 }
 
-void PrerenderContents::RenderFrameDeleted(
-    content::RenderFrameHost* render_frame_host) {
-  render_frame_hosts_.erase(render_frame_host);
-}
-
 void PrerenderContents::DidStopLoading(
     content::RenderViewHost* render_view_host) {
   has_stopped_loading_ = true;