[Presentation API] 1-UA presentation support + presenter APIs.

chrome/browser/media/router/offscreen_presentation_manager_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/offscreen_presentation_manager_factory.h"
+
+#include "base/lazy_instance.h"
+#include "chrome/browser/media/router/offscreen_presentation_manager.h"
+#include "components/keyed_service/content/browser_context_dependency_manager.h"
+
+namespace media_router {
+
+namespace {
+
+base::LazyInstance<OffscreenPresentationManagerFactory> service_factory =
+    LAZY_INSTANCE_INITIALIZER;
+
+}  // namespace
+
+// static
+OffscreenPresentationManager*
+OffscreenPresentationManagerFactory::GetOrCreateForBrowserContext(
+    content::BrowserContext* context) {
+  DCHECK(context);
+  return static_cast<OffscreenPresentationManager*>(
+      service_factory.Get().GetServiceForBrowserContext(context, true));
+}
+
+OffscreenPresentationManagerFactory::OffscreenPresentationManagerFactory()
+    : BrowserContextKeyedServiceFactory(
+          "OffscreenPresentationManager",
+          BrowserContextDependencyManager::GetInstance()) {}
+OffscreenPresentationManagerFactory::~OffscreenPresentationManagerFactory() {}
+
+KeyedService* OffscreenPresentationManagerFactory::BuildServiceInstanceFor(
+    content::BrowserContext* context) const {
+  return new OffscreenPresentationManager;
+}
+
+content::BrowserContext*
+OffscreenPresentationManagerFactory::GetBrowserContextToUse(

[mark a. foltz, 2015/10/01 18:39:13]

Will this return the same OPM for a profile and any incognito context spawned
from it?

Since we are creating a new browser context for each offscreen tab, will each
get its own OPM?

[imcheng, 2015/10/06 00:59:14]

So in ReceiverPresentationServiceDelegate we explicitly get a
OffscreenPresentationManager* using the original browser context as key. So the
offscreen tab will talk to the same OPM as the controllers.

But here, this is configured to return a separate OffscreenPresentationManager
for each context, even for incognito ones. I think we can remove this function
and just use the default behavior, which is to return nullptr for incognito
contexts.

+    content::BrowserContext* context) const {
+  return context;
+}
+
+}  // namespace media_router