Fix SyncManager initialization failure crash.

chrome/browser/sync/glue/sync_backend_host.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 "build/build_config.h"
 
 #include "chrome/browser/sync/glue/sync_backend_host.h"
 
 #include <algorithm>
 #include <map>
@@ skipping 828 matching lines @@
       &SyncBackendHost::HandleSyncCycleCompletedOnFrontendLoop,
       snapshot);
 }
 
 
 void SyncBackendHost::Core::OnInitializationComplete(
     const syncer::WeakHandle<syncer::JsBackend>& js_backend,
     bool success,
     const syncer::ModelTypeSet restored_types) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
+
+  if (!success) {
+    sync_manager_->RemoveObserver(this);
+    sync_manager_->ShutdownOnSyncThread();
+    sync_manager_.reset();
+  }
+
   host_.Call(
       FROM_HERE,
       &SyncBackendHost::HandleSyncManagerInitializationOnFrontendLoop,
       js_backend, success, restored_types);
 
   if (success) {
     // Initialization is complete, so we can schedule recurring SaveChanges.
     sync_loop_->PostTask(FROM_HERE,
                          base::Bind(&Core::StartSavingChanges, this));
   }
@@ skipping 185 matching lines @@
 void SyncBackendHost::Core::DoRefreshNigori(
     const base::Closure& done_callback) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
   chrome::VersionInfo version_info;
   sync_manager_->RefreshNigori(version_info.CreateVersionString(),
                                done_callback);
 }
 
 void SyncBackendHost::Core::DoStopSyncManagerForShutdown(
     const base::Closure& closure) {
-  DCHECK(sync_manager_.get());
-  sync_manager_->StopSyncingForShutdown(closure);
+  if (sync_manager_.get()) {
+    sync_manager_->StopSyncingForShutdown(closure);
+  } else {
+    sync_loop_->PostTask(FROM_HERE, closure);
+  }
 }
 
 void SyncBackendHost::Core::DoShutdown(bool sync_disabled) {
   DCHECK_EQ(MessageLoop::current(), sync_loop_);
-  if (!sync_manager_.get())
-    return;
+  if (sync_manager_.get()) {
+    save_changes_timer_.reset();
+    sync_manager_->ShutdownOnSyncThread();
+    sync_manager_->RemoveObserver(this);
+    sync_manager_.reset();
+  }
 
-  save_changes_timer_.reset();
-  sync_manager_->ShutdownOnSyncThread();
-  sync_manager_->RemoveObserver(this);
-  sync_manager_.reset();
   chrome_sync_notification_bridge_ = NULL;
   registrar_ = NULL;
 
   if (sync_disabled)
     DeleteSyncDataFolder();
 
   sync_loop_ = NULL;
 
   host_.Reset();
 }
@@ skipping 302 matching lines @@
       FROM_HERE,
       base::Bind(&SyncBackendHost::Core::DoRefreshNigori,
                  core_.get(), sync_thread_done_callback));
 }
 
 #undef SDVLOG
 
 #undef SLOG
 
 }  // namespace browser_sync