Add instrumentation to see how often a local predictor prerender could be

chrome/browser/prerender/prerender_contents.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/prerender/prerender_contents.h"
 
 #include <algorithm>
 #include <functional>
 #include <utility>
 
@@ skipping 520 matching lines @@
   }
 
   alias_urls_.push_back(url);
   NotifyPrerenderAddAlias(url);
   return true;
 }
 
 bool PrerenderContents::Matches(
     const GURL& url,
     const SessionStorageNamespace* session_storage_namespace) const {
-  DCHECK(child_id_ == -1 || session_storage_namespace);
   if (session_storage_namespace &&
       session_storage_namespace_id_ != session_storage_namespace->id()) {
     return false;
   }
   return std::count_if(alias_urls_.begin(), alias_urls_.end(),
                        std::bind2nd(std::equal_to<GURL>(), url)) != 0;
 }
 
 void PrerenderContents::RenderViewGone(base::TerminationStatus status) {
   Destroy(FINAL_STATUS_RENDERER_CRASHED);
@@ skipping 149 matching lines @@
 
 bool PrerenderContents::IsCrossSiteNavigationPending() const {
   if (!prerender_contents_)
     return false;
   return (prerender_contents_->GetSiteInstance() !=
           prerender_contents_->GetPendingSiteInstance());
 }
 
 
 }  // namespace prerender