Properly handle user cancellation of signin.

chrome/browser/ui/webui/sync_setup_handler.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/webui/sync_setup_handler.h"
 
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
@@ skipping 190 matching lines @@
   if (browser) {
     TabStripModel* tab_strip_model = browser->tab_strip_model();
     if (tab_strip_model) {
       int index = tab_strip_model->GetIndexOfWebContents(web_contents);
       if (index != TabStripModel::kNoTab)
         tab_strip_model->ActivateTabAt(index, false);
     }
   }
 }
 
+void CloseTab(content::WebContents* tab) {
+  Browser* browser = chrome::FindBrowserWithWebContents(tab);
+  if (browser) {
+    TabStripModel* tab_strip_model = browser->tab_strip_model();
+    if (tab_strip_model) {
+      int index = tab_strip_model->GetIndexOfWebContents(tab);
+      if (index != TabStripModel::kNoTab) {
+        tab_strip_model->ExecuteContextMenuCommand(
+            index, TabStripModel::CommandCloseTab);
+      }
+    }
+  }
+}
+
 }  // namespace
 
 SyncSetupHandler::SyncSetupHandler(ProfileManager* profile_manager)
     : configuring_sync_(false),
       profile_manager_(profile_manager),
       last_signin_error_(GoogleServiceAuthError::NONE),
       retry_on_signin_failure_(true),
       active_gaia_signin_tab_(NULL) {
 }
 
@@ skipping 1045 matching lines @@
   backend_start_timer_.reset();
 
   CloseSyncSetup();
   web_ui()->CallJavascriptFunction("OptionsPage.closeOverlay");
 }
 
 void SyncSetupHandler::CloseGaiaSigninPage() {
   if (active_gaia_signin_tab_) {
     content::WebContentsObserver::Observe(NULL);
 
-    Browser* browser = chrome::FindBrowserWithWebContents(
-        active_gaia_signin_tab_);
-    if (browser) {
-      TabStripModel* tab_strip_model = browser->tab_strip_model();
-      if (tab_strip_model) {
-        int index = tab_strip_model->GetIndexOfWebContents(
-            active_gaia_signin_tab_);
-        if (index != TabStripModel::kNoTab) {
-          tab_strip_model->ExecuteContextMenuCommand(
-              index, TabStripModel::CommandCloseTab);
-        }
-      }
-    }
+    // This can be invoked from a webui handler in the GAIA page (for example,
+    // if the user clicks 'cancel' in the enterprise signin dialog), so
+    // closing this tab in mid-handler can cause crashes. Instead, close it
+    // via a task so we know we aren't in the middle of any webui code.
+    MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(&CloseTab, base::Unretained(active_gaia_signin_tab_)));
+
+    active_gaia_signin_tab_ = NULL;
   }
-
-  active_gaia_signin_tab_ = NULL;
 }
 
 bool SyncSetupHandler::IsLoginAuthDataValid(const std::string& username,
                                             string16* error_message) {
   if (username.empty())
     return true;
 
   // Can be null during some unit tests.
   if (!web_ui())
     return true;
@@ skipping 17 matching lines @@
     if (i != current_profile_index && AreUserNamesEqual(
         cache.GetUserNameOfProfileAtIndex(i), username_utf16)) {
       *error_message = l10n_util::GetStringUTF16(
           IDS_SYNC_USER_NAME_IN_USE_ERROR);
       return false;
     }
   }
 
   return true;
 }