[MediaRouter] Adds GetPresentationServiceDelegate impl to ChromeContentBrowserClient

chrome/browser/media/router/presentation_service_delegate_impl.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/presentation_service_delegate_impl.h"
 
 #include <string>
 
 #include "base/containers/scoped_ptr_hash_map.h"
 #include "base/guid.h"
@@ skipping 309 matching lines @@
         scoped_ptr<PresentationFrame>(
             new PresentationFrame(web_contents_, router_)));
   }
   return presentation_frames_.get(render_frame_host_id);
 }
 
 void PresentationFrameManager::SetMediaRouterForTest(MediaRouter* router) {
   router_ = router;
 }
 
+PresentationServiceDelegateImpl*
+PresentationServiceDelegateImpl::GetOrCreateForWebContents(
+    content::WebContents* web_contents) {
+  DCHECK(web_contents);
+  // CreateForWebContents does nothing if the delegate instance already exists.
+  PresentationServiceDelegateImpl::CreateForWebContents(web_contents);
+  return PresentationServiceDelegateImpl::FromWebContents(web_contents);
+}
+
 PresentationServiceDelegateImpl::PresentationServiceDelegateImpl(
     content::WebContents* web_contents)
     : web_contents_(web_contents),
       router_(MediaRouterMojoImplFactory::GetApiForBrowserContext(
           web_contents_->GetBrowserContext())),
       frame_manager_(new PresentationFrameManager(web_contents, router_)),
       weak_factory_(this) {
   DCHECK(web_contents_);
   DCHECK(router_);
 }
@@ skipping 166 matching lines @@
 bool PresentationServiceDelegateImpl::HasScreenAvailabilityListenerForTest(
     int render_process_id,
     int render_frame_id,
     const MediaSource::Id& source_id) const {
   RenderFrameHostId render_frame_host_id(render_process_id, render_frame_id);
   return frame_manager_->HasScreenAvailabilityListenerForTest(
       render_frame_host_id, source_id);
 }
 
 }  // namespace media_router