Additional fixes for prerender/instant + browsing history.

chrome/browser/prerender/prerender_manager.cc

 // Copyright (c) 2011 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 <string>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 483 matching lines @@
     MarkTabContentsAsWouldBePrerendered(tab_contents);
     return false;
   }
 
   if (prerender_contents->starting_page_id() <=
       tab_contents->GetMaxPageID()) {
     prerender_contents.release()->Destroy(FINAL_STATUS_PAGE_ID_CONFLICT);
     return false;
   }
 
+  // If the prerendered page is in the middle of a cross-site navigation,
+  // don't swap it in because there isn't a good way to merge histories.
+  if (prerender_contents->IsCrossSiteNavigationPending()) {
+    prerender_contents.release()->Destroy(
+        FINAL_STATUS_CROSS_SITE_NAVIGATION_PENDING);
+    return false;
+  }
+
   int child_id, route_id;
   CHECK(prerender_contents->GetChildId(&child_id));
   CHECK(prerender_contents->GetRouteId(&route_id));
 
   // Try to set the prerendered page as used, so any subsequent attempts to
   // cancel on other threads will fail.  If this fails because the prerender
   // was already cancelled, possibly on another thread, fail.
   if (!prerender_tracker_->TryUse(child_id, route_id))
     return false;
 
@@ skipping 586 matching lines @@
   return last_origin_;
 }
 
 bool PrerenderManager::IsOriginExperimentWash() const {
   if (!WithinWindow())
     return false;
   return origin_experiment_wash_;
 }
 
 }  // namespace prerender