Fix chromium-os:10777 and other sync related crashes.

chrome/browser/dom_ui/options/personal_options_handler.cc

 // Copyright (c) 2010 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/dom_ui/options/personal_options_handler.h"
 
 #include <string>
 
 #include "app/l10n_util.h"
 #include "base/basictypes.h"
@@ skipping 136 matching lines @@
   if (type == NotificationType::BROWSER_THEME_CHANGED)
     ObserveThemeChanged();
   else
     OptionsPageUIHandler::Observe(type, source, details);
 }
 
 void PersonalOptionsHandler::OnStateChanged() {
   string16 status_label;
   string16 link_label;
   ProfileSyncService* service = dom_ui_->GetProfile()->GetProfileSyncService();
+  DCHECK(service);

[akalin, 2011/01/14 00:26:37]

I prefer these to be CHECK()s since you're dereferencing them immediately after,
but I leave it to you

   bool managed = service->IsManaged();
   bool sync_setup_completed = service->HasSyncSetupCompleted();
   bool status_has_error = sync_ui_util::GetStatusLabels(service,
       &status_label, &link_label) == sync_ui_util::SYNC_ERROR;
 
   string16 start_stop_button_label;
   bool is_start_stop_button_visible = false;
   bool is_start_stop_button_enabled = false;
   if (sync_setup_completed) {
     start_stop_button_label =
@@ skipping 101 matching lines @@
 void PersonalOptionsHandler::ShowSyncLoginDialog(const ListValue* args) {
 #if defined(OS_CHROMEOS)
   std::string email = chromeos::UserManager::Get()->logged_in_user().email();
   string16 message = l10n_util::GetStringFUTF16(
       IDS_SYNC_LOGIN_INTRODUCTION,
       l10n_util::GetStringUTF16(IDS_PRODUCT_NAME));
   dom_ui_->GetProfile()->GetBrowserSignin()->RequestSignin(
       dom_ui_->tab_contents(), UTF8ToUTF16(email), message, this);
 #else
   ProfileSyncService* service = dom_ui_->GetProfile()->GetProfileSyncService();
+  DCHECK(service);
   service->ShowLoginDialog(NULL);
   ProfileSyncService::SyncEvent(ProfileSyncService::START_FROM_OPTIONS);
 #endif
 }
 
 void PersonalOptionsHandler::ThemesReset(const ListValue* args) {
   UserMetricsRecordAction(UserMetricsAction("Options_ThemesReset"));
   dom_ui_->GetProfile()->ClearTheme();
 }
 
 #if defined(TOOLKIT_GTK)
 void PersonalOptionsHandler::ThemesSetGTK(const ListValue* args) {
   UserMetricsRecordAction(UserMetricsAction("Options_GtkThemeSet"));
   dom_ui_->GetProfile()->SetNativeTheme();
 }
 #endif
 
 void PersonalOptionsHandler::OnLoginSuccess() {
   OnStateChanged();
 }
 
 void PersonalOptionsHandler::OnLoginFailure(
     const GoogleServiceAuthError& error) {
   OnStateChanged();
 }