Remove PrerenderResourceThrottle and related infrastructure.

chrome/browser/prerender/prerender_contents.cc

Index: chrome/browser/prerender/prerender_contents.cc
diff --git a/chrome/browser/prerender/prerender_contents.cc b/chrome/browser/prerender/prerender_contents.cc
index 113a6529490cb35662c35524f66b1e043418e74a..ee069f90fd6db2a094a6b5ca5519e44f2a1b83fc 100644
--- a/chrome/browser/prerender/prerender_contents.cc
+++ b/chrome/browser/prerender/prerender_contents.cc
@@ -415,9 +415,6 @@ PrerenderContents::~PrerenderContents() {
   // destroy it.
   if (prerender_contents_.get())
     delete ReleasePrerenderContents();
-
-  // The following URLs are no longer rendering.
-  prerender_tracker_->RemovePrerenderURLsOnUIThread(alias_urls_);
 }
 
 void PrerenderContents::Observe(int type,
@@ -522,7 +519,6 @@ bool PrerenderContents::AddAliasURL(const GURL& url) {
 
   alias_urls_.push_back(url);
   InformRenderProcessAboutPrerender(url, true, creator_child_id_);
-  prerender_tracker_->AddPrerenderURLOnUIThread(url);
   return true;
 }
 
@@ -532,7 +528,6 @@ void PrerenderContents::AddAliasURLsFromOtherPrerenderContents(
        it != other_pc->alias_urls_.end();
        ++it) {
     alias_urls_.push_back(*it);
-    prerender_tracker_->AddPrerenderURLOnUIThread(*it);
   }
 }