[Media Router] Add Media Router Mojo impl code.

chrome/browser/media/router/media_router_mojo_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_mojo_impl_factory.h"
+
+#include "chrome/browser/media/router/media_router_mojo_impl.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+#include "extensions/browser/process_manager_factory.h"
+
+using content::BrowserContext;
+
+namespace media_router {
+
+namespace {
+
+base::LazyInstance<MediaRouterMojoImplFactory> service_factory =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+// static
+MediaRouterMojoImpl* MediaRouterMojoImplFactory::GetApiForBrowserContext(
+    BrowserContext* context) {
+  DCHECK(context);
+
+  return static_cast<MediaRouterMojoImpl*>(
+      service_factory.Get().GetServiceForBrowserContext(context, true));
+}
+
+MediaRouterMojoImplFactory::MediaRouterMojoImplFactory()
+    : BrowserContextKeyedServiceFactory(
+          "MediaRouterMojoImpl",
+          BrowserContextDependencyManager::GetInstance()) {
+  // MediaRouterMojoImpl depends on ProcessManager.
+  DependsOn(extensions::ProcessManagerFactory::GetInstance());
+}
+
+MediaRouterMojoImplFactory::~MediaRouterMojoImplFactory() {
+}
+
+KeyedService* MediaRouterMojoImplFactory::BuildServiceInstanceFor(
+    BrowserContext* context) const {
+  return new MediaRouterMojoImpl();
+}
+
+BrowserContext* MediaRouterMojoImplFactory::GetBrowserContextToUse(
+    BrowserContext* context) const {
+  // Always use the input context. This means that an incognito context will
+  // have its own MediaRouterMojoImpl service, rather than sharing it with its
+  // original non-incognito context.
+  return context;
+}
+
+}  // namespace media_router