Additional fixes for prerender/instant + browsing history.

chrome/browser/prerender/prerender_contents.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_contents.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/process_util.h"
@@ skipping 70 matching lines @@
 
   // TabContentsDelegate implementation:
   virtual bool ShouldAddNavigationToHistory(
       const history::HistoryAddPageArgs& add_page_args,
       NavigationType::Type navigation_type) OVERRIDE {
     add_page_vector_.push_back(
         scoped_refptr<history::HistoryAddPageArgs>(add_page_args.Clone()));
     return false;
   }
 
-  bool CanDownload(TabContents* source, int request_id) OVERRIDE {
+  virtual bool CanDownload(TabContents* source, int request_id) OVERRIDE {
     prerender_contents_->Destroy(FINAL_STATUS_DOWNLOAD);
     // Cancel the download.
     return false;
   }
 
-  void OnStartDownload(TabContents* source, DownloadItem* download) OVERRIDE {
+  virtual void OnStartDownload(TabContents* source,
+                               DownloadItem* download) OVERRIDE {
     // Prerendered pages should never be able to download files.
     NOTREACHED();
   }
 
+  virtual bool OnGoToEntryOffset(int offset) OVERRIDE {
+    // This isn't allowed because the history merge operation
+    // does not work if there are renderer issued challenges.
+    // TODO(cbentzel): Cancel in this case? May not need to do
+    // since render-issued offset navigations are not guaranteed,
+    // but indicates that the page cares about the history.
+    return false;
+  }
+
   // Commits the History of Pages to the given TabContents.
   void CommitHistory(TabContentsWrapper* tab) {
     for (size_t i = 0; i < add_page_vector_.size(); ++i)
       tab->history_tab_helper()->UpdateHistoryForNavigation(
           add_page_vector_[i].get());
   }
 
  private:
   typedef std::vector<scoped_refptr<history::HistoryAddPageArgs> >
       AddPageVector;
@@ skipping 483 matching lines @@
   if (!prerender_contents_.get())
     return NULL;
   DictionaryValue* dict_value = new DictionaryValue();
   dict_value->SetString("url", prerender_url_.spec());
   base::TimeTicks current_time = base::TimeTicks::Now();
   base::TimeDelta duration = current_time - load_start_time_;
   dict_value->SetInteger("duration", duration.InSeconds());
   return dict_value;
 }
 
+bool PrerenderContents::IsCrossSiteNavigationPending() const {
+  if (!prerender_contents_.get() || !prerender_contents_->tab_contents())
+    return false;
+  const TabContents* tab_contents = prerender_contents_->tab_contents();
+  return (tab_contents->GetSiteInstance() !=
+          tab_contents->GetPendingSiteInstance());
+}
+
+
 }  // namespace prerender