[NoStatePrefetch] Don't cancel prefetches when there are duplicates

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 923 matching lines @@
   if (prerendering_status != NetworkPredictionStatus::ENABLED) {
     FinalStatus final_status =
         prerendering_status == NetworkPredictionStatus::DISABLED_DUE_TO_NETWORK
             ? FINAL_STATUS_CELLULAR_NETWORK
             : FINAL_STATUS_PRERENDERING_DISABLED;
     RecordFinalStatusWithoutCreatingPrerenderContents(url, origin,
                                                       final_status);
     return nullptr;
   }
 
+  if (PrerenderData* preexisting_prerender_data =
+                 FindPrerenderData(url, session_storage_namespace)) {
+    RecordFinalStatusWithoutCreatingPrerenderContents(
+        url, origin, FINAL_STATUS_DUPLICATE);
+    return base::WrapUnique(new PrerenderHandle(preexisting_prerender_data));
+  }
+
   if (IsNoStatePrefetch(origin)) {
     base::TimeDelta prefetch_age;
     GetPrefetchInformation(url, &prefetch_age, nullptr);
     if (!prefetch_age.is_zero() &&
         prefetch_age <
             base::TimeDelta::FromMinutes(net::HttpCache::kPrefetchReuseMins)) {
       RecordFinalStatusWithoutCreatingPrerenderContents(url, origin,
                                                         FINAL_STATUS_DUPLICATE);
       return nullptr;
     }
-  } else if (PrerenderData* preexisting_prerender_data =
-                 FindPrerenderData(url, session_storage_namespace)) {
-    RecordFinalStatusWithoutCreatingPrerenderContents(
-        url, origin, FINAL_STATUS_DUPLICATE);
-    return base::WrapUnique(new PrerenderHandle(preexisting_prerender_data));
   }
 
   // Do not prerender if there are too many render processes, and we would
   // have to use an existing one.  We do not want prerendering to happen in
   // a shared process, so that we can always reliably lower the CPU
   // priority for prerendering.
   // In single-process mode, ShouldTryToUseExistingProcessHost() always returns
   // true, so that case needs to be explicitly checked for.
   // TODO(tburkard): Figure out how to cancel prerendering in the opposite
   // case, when a new tab is added to a process used for prerendering.
@@ skipping 468 matching lines @@
   return weak_factory_.GetWeakPtr();
 }
 
 void PrerenderManager::SetPrerenderContentsFactoryForTest(
     PrerenderContents::Factory* prerender_contents_factory) {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   prerender_contents_factory_.reset(prerender_contents_factory);
 }
 
 }  // namespace prerender