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

chrome/browser/favicon/chrome_fallback_icon_client_factory.h

 // 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.
 
-#ifndef CHROME_BROWSER_UI_BOOKMARKS_ENHANCED_BOOKMARK_KEY_SERVICE_FACTORY_H_
-#define CHROME_BROWSER_UI_BOOKMARKS_ENHANCED_BOOKMARK_KEY_SERVICE_FACTORY_H_
+#ifndef CHROME_BROWSER_FAVICON_CHROME_FALLBACK_ICON_CLIENT_FACTORY_H_
+#define CHROME_BROWSER_FAVICON_CHROME_FALLBACK_ICON_CLIENT_FACTORY_H_
 
-#include "base/macros.h"
 #include "components/keyed_service/content/browser_context_keyed_service_factory.h"
 
+template <typename T> struct DefaultSingletonTraits;
+
+class FallbackIconClient;
+
 namespace content {
 class BrowserContext;
-}  // namespace content
+}
 
-template <typename T> struct DefaultSingletonTraits;
-
-class EnhancedBookmarkKeyService;
-
-// Singleton that owns all EnhancedBookmarkKeyServices and associates them with
-// BrowserContexts.
-class EnhancedBookmarkKeyServiceFactory
+// Singleton that owns all ChromeFallbackIconClients and associates them with
+// Profiles.
+class ChromeFallbackIconClientFactory
     : public BrowserContextKeyedServiceFactory {
  public:
-  static EnhancedBookmarkKeyServiceFactory* GetInstance();
+  // Returns the instance of FallbackIconClient associated with this profile
+  // (creating one if none exists).
+  static FallbackIconClient* GetForBrowserContext(
+      content::BrowserContext* context);
+
+  // Returns an instance of the factory singleton.
+  static ChromeFallbackIconClientFactory* GetInstance();
 
  private:
-  friend struct DefaultSingletonTraits<EnhancedBookmarkKeyServiceFactory>;
+  friend struct DefaultSingletonTraits<ChromeFallbackIconClientFactory>;
 
-  EnhancedBookmarkKeyServiceFactory();
-  ~EnhancedBookmarkKeyServiceFactory() override;
+  ChromeFallbackIconClientFactory();
+  ~ChromeFallbackIconClientFactory() override;
 
   // BrowserContextKeyedServiceFactory:
   KeyedService* BuildServiceInstanceFor(
       content::BrowserContext* context) const override;
-  content::BrowserContext* GetBrowserContextToUse(
-      content::BrowserContext* context) const override;
-  bool ServiceIsCreatedWithBrowserContext() const override;
-  bool ServiceIsNULLWhileTesting() const override;
-
-  DISALLOW_COPY_AND_ASSIGN(EnhancedBookmarkKeyServiceFactory);
 };
 
-#endif  // CHROME_BROWSER_UI_BOOKMARKS_ENHANCED_BOOKMARK_KEY_SERVICE_FACTORY_H_
+#endif  // CHROME_BROWSER_FAVICON_CHROME_FALLBACK_ICON_CLIENT_FACTORY_H_