Ensure we don't crash if user navigates back from NTP to Chrome sign-in page before it has fully lo…

chrome/browser/ui/sync/one_click_signin_helper.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/ui/sync/one_click_signin_helper.h"
 
 #include <algorithm>
 #include <functional>
 #include <utility>
 #include <vector>
@@ skipping 452 matching lines @@
 // We have to delay the cleaning until the new URL has finished loading because
 // we're not allowed to remove the last-loaded URL from the history.  Objects
 // of this type automatically self-destruct once they're finished their work.
 class CurrentHistoryCleaner : public content::WebContentsObserver {
  public:
   explicit CurrentHistoryCleaner(content::WebContents* contents);
   virtual ~CurrentHistoryCleaner();
 
   // content::WebContentsObserver:
   virtual void WebContentsDestroyed(content::WebContents* contents) OVERRIDE;
-  virtual void DidStopLoading(
-      content::RenderViewHost* render_view_host) OVERRIDE;
+  virtual void DidNavigateMainFrame(
+      const content::LoadCommittedDetails& details,
+      const content::FrameNavigateParams& params) OVERRIDE;
 
  private:
   scoped_ptr<content::WebContents> contents_;
   int history_index_to_remove_;
 
   DISALLOW_COPY_AND_ASSIGN(CurrentHistoryCleaner);
 };
 
 CurrentHistoryCleaner::CurrentHistoryCleaner(content::WebContents* contents)
     : WebContentsObserver(contents) {
   history_index_to_remove_ =
       web_contents()->GetController().GetLastCommittedEntryIndex();
 }
 
 CurrentHistoryCleaner::~CurrentHistoryCleaner() {
 }
 
-void CurrentHistoryCleaner::DidStopLoading(
-    content::RenderViewHost* render_view_host) {
+void CurrentHistoryCleaner::DidNavigateMainFrame(
+    const content::LoadCommittedDetails& details,
+    const content::FrameNavigateParams& params) {
   content::NavigationController* nc = &web_contents()->GetController();
   // Have to wait until something else gets added to history before removal.
   if (history_index_to_remove_ < nc->GetLastCommittedEntryIndex()) {
-    nc->RemoveEntryAtIndex(history_index_to_remove_);
-    delete this;  // Success.
+    if (nc->RemoveEntryAtIndex(history_index_to_remove_))
+      delete this;  // Success.
   }
 }
 
 void CurrentHistoryCleaner::WebContentsDestroyed(
     content::WebContents* contents) {
   delete this;  // Failure.
 }
 
 void CloseTab(content::WebContents* tab) {
   Browser* browser = chrome::FindBrowserWithWebContents(tab);
@@ skipping 803 matching lines @@
                                         content::Referrer(),
                                         content::PAGE_TRANSITION_AUTO_TOPLEVEL,
                                         std::string());
     }
   }
 
   // Clear the redirect URL.
   redirect_url_ = GURL();
   sync_service->RemoveObserver(this);
 }