Add ExternalPrerenderRequestHandler and related API

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index 954edb55bb6d2bfff58f8189336f8b0ef0ab520a..7a3efcf6f231ff395427ee73f20d1e099fe83899 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -392,6 +392,15 @@ PrerenderHandle* PrerenderManager::AddPrerenderFromLocalPredictor(
                       size, session_storage_namespace);
 }
 
+PrerenderHandle* PrerenderManager::AddPrerenderFromExternalRequest(
+    const GURL& url,
+    const content::Referrer& referrer,
+    SessionStorageNamespace* session_storage_namespace,
+    const gfx::Size& size) {
+  return AddPrerender(ORIGIN_EXTERNAL_REQUEST, -1, url, referrer, size,
+                      session_storage_namespace);
+}
+
 void PrerenderManager::DestroyPrerenderForRenderView(
     int process_id, int view_id, FinalStatus final_status) {
   DCHECK(CalledOnValidThread());
@@ -785,6 +794,23 @@ bool PrerenderManager::IsWebContentsPrerendering(
   return false;
 }
 
+bool PrerenderManager::HasPrerenderedUrl(
+    GURL url,
+    content::WebContents* web_contents) const {
+  content::SessionStorageNamespace* session_storage_namespace = web_contents->
+      GetController().GetDefaultSessionStorageNamespace();
+
+  for (ScopedVector<PrerenderData>::const_iterator it =
+           active_prerenders_.begin();
+       it != active_prerenders_.end(); ++it) {
+    PrerenderContents* prerender_contents = (*it)->contents();
+    if (prerender_contents->Matches(url, session_storage_namespace)) {
+      return true;
+    }
+  }
+  return false;
+}
+
 PrerenderContents* PrerenderManager::GetPrerenderContents(
     const content::WebContents* web_contents) const {
   DCHECK(CalledOnValidThread());