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 458 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(
+  virtual void DidCommitProvisionalLoadForFrame(
+      int64 frame_id,
+      bool is_main_frame,
+      const GURL& url,
+      content::PageTransition transition_type,
       content::RenderViewHost* render_view_host) 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(
+void CurrentHistoryCleaner::DidCommitProvisionalLoadForFrame(
+    int64 frame_id,
+    bool is_main_frame,
+    const GURL& url,
+    content::PageTransition transition_type,
     content::RenderViewHost* render_view_host) {
+  // Return early if this is not top-level navigation.
+  if (!is_main_frame)
+    return;
+
   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.
+    content::NavigationEntry* entry =
+        nc->GetEntryAtIndex(history_index_to_remove_);
+    if (SyncPromoUI::IsContinueUrlForWebBasedSigninFlow(entry->GetURL()) &&
+        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 384 matching lines @@
     helper->email_ = email;
 
   if (continue_url.is_valid())
     helper->continue_url_ = continue_url;
 }
 
 // static
 void OneClickSigninHelper::RemoveSigninRedirectURLHistoryItem(
     content::WebContents* web_contents) {
   // Only actually remove the item if it's the blank.html continue url.
-  if (SyncPromoUI::IsContinueUrlForWebBasedSigninFlow(web_contents->GetURL()))
+  if (SyncPromoUI::IsContinueUrlForWebBasedSigninFlow(
+          web_contents->GetLastCommittedURL())) {
     new CurrentHistoryCleaner(web_contents);  // will self-destruct when done
+  }
 }
 
 void OneClickSigninHelper::ShowSigninErrorBubble(Browser* browser,
                                                  const std::string& error) {
   DCHECK(!error.empty());
 
   browser->window()->ShowOneClickSigninBubble(
       BrowserWindow::ONE_CLICK_SIGNIN_BUBBLE_TYPE_BUBBLE,
       string16(), /* no SAML email */
       UTF8ToUTF16(error),
@@ skipping 113 matching lines @@
     if (manager && manager->IsSigninProcess(process_id))
       manager->ClearSigninProcess();
   }
 }
 
 void OneClickSigninHelper::DidStopLoading(
     content::RenderViewHost* render_view_host) {
   // If the user left the sign in process, clear all members.
   // TODO(rogerta): might need to allow some youtube URLs.
   content::WebContents* contents = web_contents();
-  const GURL url = contents->GetURL();
+  const GURL url = contents->GetLastCommittedURL();
   Profile* profile =
       Profile::FromBrowserContext(contents->GetBrowserContext());
   VLOG(1) << "OneClickSigninHelper::DidStopLoading: url=" << url.spec();
 
   // If an error has already occured during the sign in flow, make sure to
   // display it to the user and abort the process.  Do this only for
   // explicit sign ins.
   // TODO(rogerta): Could we move this code back up to ShowInfoBarUIThread()?
   if (!error_message_.empty() && auto_accept_ == AUTO_ACCEPT_EXPLICIT) {
     VLOG(1) << "OneClickSigninHelper::DidStopLoading: error=" << error_message_;
@@ skipping 263 matching lines @@
                                         content::Referrer(),
                                         content::PAGE_TRANSITION_AUTO_TOPLEVEL,
                                         std::string());
     }
   }
 
   // Clear the redirect URL.
   redirect_url_ = GURL();
   sync_service->RemoveObserver(this);
 }