Prerender: Add timeout to appcache waiting in NoStatePrefetch browser test.

chrome/browser/prerender/prerender_nostate_prefetch_browsertest.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 "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/stl_util.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_split.h"
@@ skipping 102 matching lines @@
     content::AppCacheService* appcache_service =
         content::BrowserContext::GetDefaultStoragePartition(
             current_browser()->profile())
             ->GetAppCacheService();
     do {
       base::RunLoop wait_loop;
       content::BrowserThread::PostTask(
           content::BrowserThread::IO, FROM_HERE,
           base::BindOnce(WaitForAppcacheOnIO, manifest_url, appcache_service,
                          wait_loop.QuitClosure(), &found_manifest));
+      // There seems to be some flakiness in the appcache getting back to us, so
+      // use a timeout task to try the appcache query again.
+      content::BrowserThread::PostDelayedTask(
+          content::BrowserThread::UI, FROM_HERE, wait_loop.QuitClosure(),
+          base::TimeDelta::FromMilliseconds(2000));
       wait_loop.Run();
     } while (!found_manifest);
   }
 
  protected:
   std::unique_ptr<TestPrerender> PrefetchFromURL(
       const GURL& target_url,
       FinalStatus expected_final_status) {
     GURL loader_url = ServeLoaderURL(
         kPrefetchLoaderPath, "REPLACE_WITH_PREFETCH_URL", target_url, "");
@@ skipping 619 matching lines @@
   CountRequestFor(kPrefetchPage, &page_counter);
   RequestCounter script_counter;
   CountRequestFor(kPrefetchScript, &script_counter);
   PrefetchFromURL(prefetch_page_url, FINAL_STATUS_NOSTATE_PREFETCH_FINISHED);
   // Neither the page nor the script should be prefetched.
   script_counter.WaitForCount(0);
   page_counter.WaitForCount(0);
 }
 
 }  // namespace prerender