Revert of [Media Router] Design MediaRouter interface with stub implementation.

chrome/browser/media/router/media_router_impl_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/media/router/media_router_impl_factory.h"
-
-#include "chrome/browser/media/router/media_router_impl.h"
-#include "components/keyed_service/content/browser_context_dependency_manager.h"
-
-using content::BrowserContext;
-
-namespace media_router {
-
-// static
-MediaRouterImpl* MediaRouterImplFactory::GetMediaRouterForBrowserContext(
-    BrowserContext* context) {
-  DCHECK(context);
-  return static_cast<MediaRouterImpl*>(
-      GetInstance()->GetServiceForBrowserContext(context, true));
-}
-
-// static
-MediaRouterImplFactory* MediaRouterImplFactory::GetInstance() {
-  return Singleton<MediaRouterImplFactory>::get();
-}
-
-MediaRouterImplFactory::MediaRouterImplFactory()
-    : BrowserContextKeyedServiceFactory(
-          "MediaRouterImpl",
-          BrowserContextDependencyManager::GetInstance()) {
-}
-
-MediaRouterImplFactory::~MediaRouterImplFactory() {
-}
-
-KeyedService* MediaRouterImplFactory::BuildServiceInstanceFor(
-    BrowserContext* context) const {
-  return new MediaRouterImpl;
-}
-
-BrowserContext* MediaRouterImplFactory::GetBrowserContextToUse(
-    BrowserContext* context) const {
-  // This means MediaRouterImpl is available in incognito contexts as well.
-  return context;
-}
-
-}  // namespace media_router