[Fallback Icons] Refactor FallbackIconService to be a BrowserContext-level singleton

chrome/browser/favicon/chrome_fallback_icon_client_factory.cc

-// Copyright 2014 The Chromium Authors. All rights reserved.
+// Copyright 2015 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 "extensions/browser/extension_pref_value_map_factory.h"
+#include "chrome/browser/favicon/chrome_fallback_icon_client_factory.h"
 
+#include "base/memory/singleton.h"
+#include "chrome/browser/favicon/chrome_fallback_icon_client.h"
+#include "chrome/browser/profiles/incognito_helpers.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
-#include "extensions/browser/extension_pref_value_map.h"
+#include "content/public/browser/browser_context.h"
 
-ExtensionPrefValueMapFactory::ExtensionPrefValueMapFactory()
+ChromeFallbackIconClientFactory::ChromeFallbackIconClientFactory()
     : BrowserContextKeyedServiceFactory(
-        "ExtensionPrefValueMap",
+        "ChromeFallbackIconClient",
         BrowserContextDependencyManager::GetInstance()) {
 }
 
-ExtensionPrefValueMapFactory::~ExtensionPrefValueMapFactory() {
+ChromeFallbackIconClientFactory::~ChromeFallbackIconClientFactory() {
 }
 
 // static
-ExtensionPrefValueMap* ExtensionPrefValueMapFactory::GetForBrowserContext(
+FallbackIconClient* ChromeFallbackIconClientFactory::GetForBrowserContext(
     content::BrowserContext* context) {
-  return static_cast<ExtensionPrefValueMap*>(
+  return static_cast<FallbackIconClient*>(
       GetInstance()->GetServiceForBrowserContext(context, true));
 }
 
 // static
-ExtensionPrefValueMapFactory* ExtensionPrefValueMapFactory::GetInstance() {
-  return Singleton<ExtensionPrefValueMapFactory>::get();
+ChromeFallbackIconClientFactory*
+ChromeFallbackIconClientFactory::GetInstance() {
+  return Singleton<ChromeFallbackIconClientFactory>::get();
 }
 
-KeyedService* ExtensionPrefValueMapFactory::BuildServiceInstanceFor(
+KeyedService* ChromeFallbackIconClientFactory::BuildServiceInstanceFor(
     content::BrowserContext* context) const {
-  return new ExtensionPrefValueMap();
+  return new ChromeFallbackIconClient();
 }