android: Add a method to let Java know whether a prerender has finished loading.

chrome/browser/prerender/prerender_manager.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_manager.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <functional>
@@ skipping 644 matching lines @@
   }
   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)) {
+  for (const auto& prerender_data : active_prerenders_) {

[gavinp, 2016/02/25 18:44:55]

Thanks. This is closely related and so refactoring this function is a good idea.

+    PrerenderContents* prerender_contents = prerender_data->contents();
+    if (prerender_contents->Matches(url, session_storage_namespace))
       return true;
-    }
   }
   return false;
 }
+
+bool PrerenderManager::HasPrerenderedAndFinishedLoadingUrl(
+    GURL url,
+    content::WebContents* web_contents) const {
+  content::SessionStorageNamespace* session_storage_namespace =
+      web_contents->GetController().GetDefaultSessionStorageNamespace();
+
+  for (const auto& prerender_data : active_prerenders_) {
+    PrerenderContents* prerender_contents = prerender_data->contents();
+    if (prerender_contents->Matches(url, session_storage_namespace) &&
+        prerender_contents->has_finished_loading())
+      return true;
+  }
+  return false;
+}
 
 PrerenderContents* PrerenderManager::GetPrerenderContents(
     const content::WebContents* web_contents) const {
   DCHECK(CalledOnValidThread());
   for (ScopedVector<PrerenderData>::const_iterator it =
            active_prerenders_.begin();
        it != active_prerenders_.end(); ++it) {
     WebContents* prerender_web_contents =
         (*it)->contents()->prerender_contents();
     if (prerender_web_contents == web_contents) {
@@ skipping 614 matching lines @@
 }
 
 void PrerenderManager::RenderProcessHostDestroyed(
     content::RenderProcessHost* host) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   size_t erased = prerender_process_hosts_.erase(host);
   DCHECK_EQ(1u, erased);
 }
 
 }  // namespace prerender