Do not count image search results towards the GWS metric.

R=dominich@chromium.org, cbentzel@chromium.org
Review URL: http://codereview.chromium.org/7800010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@98812 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/prerender/prerender_manager.cc

@@ -299,7 +299,8 @@ bool PrerenderManager::AddPrerender(
   DCHECK(CalledOnValidThread());
 
   if (origin == ORIGIN_LINK_REL_PRERENDER &&
-      StartsWithASCII(referrer.host(), std::string("www.google."), true)) {
+      StartsWithASCII(referrer.host(), std::string("www.google."), true) &&
+      !StartsWithASCII(referrer.path(), std::string("/imgres"), true)) {
     origin = ORIGIN_GWS_PRERENDER;
   }