Bring up of the enhanced bookmarks cluster service.

components/enhanced_bookmarks/enhanced_bookmark_model.cc

 // Copyright 2014 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 "components/enhanced_bookmarks/enhanced_bookmark_model.h"
 
 #include <iomanip>
 #include <sstream>
 
 #include "base/base64.h"
@@ skipping 73 matching lines @@
       weak_ptr_factory_(this),
       version_(version) {
   bookmark_model_->AddObserver(this);
   if (bookmark_model_->loaded()) {
     InitializeIdMap();
     loaded_ = true;
   }
 }
 
 EnhancedBookmarkModel::~EnhancedBookmarkModel() {
+  Shutdown();
 }
 
 void EnhancedBookmarkModel::Shutdown() {
-  FOR_EACH_OBSERVER(EnhancedBookmarkModelObserver,
-                    observers_,
-                    EnhancedBookmarkModelShuttingDown());
-  weak_ptr_factory_.InvalidateWeakPtrs();
-  bookmark_model_->RemoveObserver(this);
-  bookmark_model_ = NULL;
+  if (bookmark_model_) {
+    FOR_EACH_OBSERVER(EnhancedBookmarkModelObserver,
+                      observers_,
+                      EnhancedBookmarkModelShuttingDown());
+    weak_ptr_factory_.InvalidateWeakPtrs();
+    bookmark_model_->RemoveObserver(this);
+    bookmark_model_ = NULL;
+  }
 }
 
 void EnhancedBookmarkModel::AddObserver(
     EnhancedBookmarkModelObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void EnhancedBookmarkModel::RemoveObserver(
     EnhancedBookmarkModelObserver* observer) {
   observers_.RemoveObserver(observer);
@@ skipping 373 matching lines @@
   if (!result)
     return false;
 
   std::string encoded;
   base::Base64Encode(output, &encoded);
   bookmark_model_->SetNodeMetaInfo(node, kImageDataKey, encoded);
   return true;
 }
 
 }  // namespace enhanced_bookmarks