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

chrome/browser/favicon/chrome_fallback_icon_client_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/favicon/chrome_fallback_icon_client_factory.h"
+
+#include "chrome/browser/profiles/incognito_helpers.h"
+#include "chrome/browser/profiles/profile.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+
+ChromeFallbackIconClientFactory::ChromeFallbackIconClientFactory()
+    : BrowserContextKeyedServiceFactory(
+          "ChromeFallbackIconClient",
+          BrowserContextDependencyManager::GetInstance()) {
+}
+
+ChromeFallbackIconClientFactory::~ChromeFallbackIconClientFactory() {
+}
+
+// static
+FallbackIconClient* ChromeFallbackIconClientFactory::GetForProfile(
+    Profile* profile) {
+  return static_cast<FallbackIconClient*>(
+      GetInstance()->GetServiceForBrowserContext(profile, true));
+}
+
+// static
+ChromeFallbackIconClientFactory*
+ChromeFallbackIconClientFactory::GetInstance() {
+  return Singleton<ChromeFallbackIconClientFactory>::get();
+}
+
+KeyedService* ChromeFallbackIconClientFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  ChromeFallbackIconClient* client =
+      new ChromeFallbackIconClient(Profile::FromBrowserContext(context));
+  return client;
+}
+
+content::BrowserContext*
+ChromeFallbackIconClientFactory::GetBrowserContextToUse(
+    content::BrowserContext* context) const {
+  return chrome::GetBrowserContextRedirectedInIncognito(context);
+}