Add ExtensionsApiClient interface, use it in the storage API SettingsFrontend

apps/shell/browser/shell_extensions_browser_client.cc

 // Copyright 2013 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 "apps/shell/browser/shell_extensions_browser_client.h"
 
 #include "apps/shell/browser/shell_app_sorting.h"
 #include "apps/shell/browser/shell_extension_system_factory.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/pref_service_factory.h"
 #include "base/prefs/testing_pref_store.h"
 #include "components/user_prefs/pref_registry_syncable.h"
 #include "components/user_prefs/user_prefs.h"
+#include "extensions/browser/api/extensions_api_client.h"
 #include "extensions/browser/app_sorting.h"
 #include "extensions/browser/extension_prefs.h"
 
 using content::BrowserContext;
 
 namespace extensions {
 namespace {
 
 // See chrome::RegisterProfilePrefs() in chrome/browser/prefs/browser_prefs.cc
 void RegisterPrefs(user_prefs::PrefRegistrySyncable* registry) {
   ExtensionPrefs::RegisterProfilePrefs(registry);
 }
 
 }  // namespace
 
-
 ShellExtensionsBrowserClient::ShellExtensionsBrowserClient(
     BrowserContext* context)
-    : browser_context_(context) {
+    : browser_context_(context), api_client_(new ExtensionsApiClient) {
+  ExtensionsApiClient::Set(api_client_.get());
+
   // Set up the preferences service.
   base::PrefServiceFactory factory;
   factory.set_user_prefs(new TestingPrefStore);
   factory.set_extension_prefs(new TestingPrefStore);
   // app_shell should not require syncable preferences, but for now we need to
   // recycle some of the RegisterProfilePrefs() code in Chrome.
   // TODO(jamescook): Convert this to PrefRegistrySimple.
   user_prefs::PrefRegistrySyncable* pref_registry =
       new user_prefs::PrefRegistrySyncable;
   // Prefs should be registered before the PrefService is created.
   RegisterPrefs(pref_registry);
   prefs_ = factory.Create(pref_registry).Pass();
   user_prefs::UserPrefs::Set(browser_context_, prefs_.get());
 }
 
-ShellExtensionsBrowserClient::~ShellExtensionsBrowserClient() {}
+ShellExtensionsBrowserClient::~ShellExtensionsBrowserClient() {
+  ExtensionsApiClient::Set(NULL);
+}
 
 bool ShellExtensionsBrowserClient::IsShuttingDown() {
   return false;
 }
 
 bool ShellExtensionsBrowserClient::AreExtensionsDisabled(
     const CommandLine& command_line,
     BrowserContext* context) {
   return false;
 }
@@ skipping 88 matching lines @@
   // app_shell doesn't monitor API function calls or events.
   return NULL;
 }
 
 ExtensionSystemProvider*
 ShellExtensionsBrowserClient::GetExtensionSystemFactory() {
   return ShellExtensionSystemFactory::GetInstance();
 }
 
 }  // namespace extensions