Shortcut cross-process frame transfers to avoid pending NavigationEntries.

chrome/browser/prerender/prerender_contents.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_contents.h"
 
 #include <algorithm>
 #include <functional>
 #include <utility>
 
@@ skipping 74 matching lines @@
  public:
   explicit WebContentsDelegateImpl(PrerenderContents* prerender_contents)
       : prerender_contents_(prerender_contents) {
   }
 
   // content::WebContentsDelegate implementation:
   WebContents* OpenURLFromTab(WebContents* source,
                               const OpenURLParams& params) override {
     // |OpenURLFromTab| is typically called when a frame performs a navigation
     // that requires the browser to perform the transition instead of WebKit.
-    // Examples include prerendering a site that redirects to an app URL, or if
-    // --site-per-process is specified and the prerendered frame redirects to a
-    // different origin.
+    // Examples include client redirects to hosted app URLs.
     // TODO(cbentzel): Consider supporting this for CURRENT_TAB dispositions, if
     // it is a common case during prerenders.
     prerender_contents_->Destroy(FINAL_STATUS_OPEN_URL);
     return NULL;
   }
 
+  bool ShouldTransferNavigation() override {
+    // Cancel the prerender if the navigation attempts to transfer to a
+    // different process.  Examples include server redirects to privileged pages
+    // or cross-site subframe navigations in --site-per-process.
+    prerender_contents_->Destroy(FINAL_STATUS_OPEN_URL);
+    return false;
+  }
+
   void CloseContents(content::WebContents* contents) override {
     prerender_contents_->Destroy(FINAL_STATUS_CLOSED);
   }
 
   void CanDownload(const GURL& url,
                    const std::string& request_method,
                    const base::Callback<void(bool)>& callback) override {
     prerender_contents_->Destroy(FINAL_STATUS_DOWNLOAD);
     // Cancel the download.
     callback.Run(false);
@@ skipping 637 matching lines @@
 void PrerenderContents::AddResourceThrottle(
     const base::WeakPtr<PrerenderResourceThrottle>& throttle) {
   resource_throttles_.push_back(throttle);
 }
 
 void PrerenderContents::AddNetworkBytes(int64 bytes) {
   network_bytes_ += bytes;
 }
 
 }  // namespace prerender