Get rid of PrefService::GetMutableDictionary/GetMutableList

chrome/browser/debugger/devtools_window.cc

 // Copyright (c) 2011 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 "base/command_line.h"
 #include "base/json/json_writer.h"
 #include "base/string_number_conversions.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/browser_list.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/browser_window.h"
 #include "chrome/browser/debugger/devtools_manager.h"
 #include "chrome/browser/debugger/devtools_window.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/load_notification_details.h"
 #include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/tabs/tab_strip_model.h"
 #include "chrome/browser/themes/theme_service.h"
 #include "chrome/browser/themes/theme_service_factory.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_wrapper.h"
 #include "chrome/common/bindings_policy.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
@@ skipping 195 matching lines @@
   wp_key.append(prefs::kBrowserWindowPlacement);
   wp_key.append("_");
   wp_key.append(kDevToolsApp);
 
   PrefService* prefs = profile_->GetPrefs();
   if (!prefs->FindPreference(wp_key.c_str())) {
     prefs->RegisterDictionaryPref(wp_key.c_str());
   }
 
   const DictionaryValue* wp_pref = prefs->GetDictionary(wp_key.c_str());
-  if (!wp_pref) {
-    DictionaryValue* defaults = prefs->GetMutableDictionary(wp_key.c_str());
+  if (!wp_pref || wp_pref->empty()) {
+    DictionaryPrefUpdate update(prefs, wp_key.c_str());
+    DictionaryValue* defaults = update.Get();
     defaults->SetInteger("left", 100);
     defaults->SetInteger("top", 100);
     defaults->SetInteger("right", 740);
     defaults->SetInteger("bottom", 740);
     defaults->SetBoolean("maximized", false);
     defaults->SetBoolean("always_on_top", false);
   }
 
   browser_ = Browser::CreateForDevTools(profile_);
   browser_->tabstrip_model()->AddTabContents(
@@ skipping 194 matching lines @@
   return false;
 }
 
 void DevToolsWindow::HandleKeyboardEvent(const NativeWebKeyboardEvent& event) {
   if (docked_) {
     BrowserWindow* inspected_window = GetInspectedBrowserWindow();
     if (inspected_window)
       inspected_window->HandleKeyboardEvent(event);
   }
 }