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

chrome/browser/favicon/fallback_icon_service_factory.cc

 // 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 "chrome/browser/enhanced_bookmarks/android/bookmark_image_service_android.h"
-#include "chrome/browser/enhanced_bookmarks/android/bookmark_image_service_factory.h"
+#include "chrome/browser/favicon/fallback_icon_service_factory.h"
+
+#include "base/memory/singleton.h"
+#include "chrome/browser/favicon/chrome_fallback_icon_client_factory.h"
+#include "components/favicon/core/fallback_icon_service.h"
 #include "components/keyed_service/content/browser_context_dependency_manager.h"
 #include "content/public/browser/browser_context.h"
 
-namespace enhanced_bookmarks {
-
 // static
-BookmarkImageServiceFactory* BookmarkImageServiceFactory::GetInstance() {
-  return Singleton<BookmarkImageServiceFactory>::get();
+FallbackIconService* FallbackIconServiceFactory::GetForBrowserContext(
+    content::BrowserContext* context) {
+  return static_cast<FallbackIconService*>(
+      GetInstance()->GetServiceForBrowserContext(context, true));
 }
 
 // static
-BookmarkImageService* BookmarkImageServiceFactory::GetForBrowserContext(
-    content::BrowserContext* context) {
-  return static_cast<BookmarkImageService*>(
-      GetInstance()->GetServiceForBrowserContext(context, true));
+FallbackIconServiceFactory* FallbackIconServiceFactory::GetInstance() {
+  return Singleton<FallbackIconServiceFactory>::get();
 }
 
-BookmarkImageServiceFactory::BookmarkImageServiceFactory()
+FallbackIconServiceFactory::FallbackIconServiceFactory()
     : BrowserContextKeyedServiceFactory(
-          "BookmarkExtendedStorageService",
-          BrowserContextDependencyManager::GetInstance()) {}
-
-BookmarkImageServiceFactory::~BookmarkImageServiceFactory() {}
-
-content::BrowserContext* BookmarkImageServiceFactory::GetBrowserContextToUse(
-    content::BrowserContext* context) const {
-  return context;
+        "FallbackIconService",
+        BrowserContextDependencyManager::GetInstance()) {
+  DependsOn(ChromeFallbackIconClientFactory::GetInstance());
 }
 
-BookmarkImageService* BookmarkImageServiceFactory::BuildServiceInstanceFor(
-    content::BrowserContext* browser_context) const {
-  return new BookmarkImageServiceAndroid(browser_context);
+FallbackIconServiceFactory::~FallbackIconServiceFactory() {}
+
+KeyedService* FallbackIconServiceFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  FallbackIconClient* fallback_icon_client =
+      ChromeFallbackIconClientFactory::GetForBrowserContext(context);
+  return new FallbackIconService(fallback_icon_client);
 }
 
-}  // namespace enhanced_bookmarks
+bool FallbackIconServiceFactory::ServiceIsNULLWhileTesting() const {
+  return true;
+}