[Media Router] 2nd take on fix route response callback lifetime in UI.

chrome/browser/ui/webui/media_router/media_router_dialog_controller.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/ui/webui/media_router/media_router_dialog_controller.h"
 
 #include <string>
 #include <vector>
 
+#include "chrome/browser/media/router/presentation_service_delegate_impl.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/webui/constrained_web_dialog_ui.h"
 #include "chrome/browser/ui/webui/media_router/media_router_ui.h"
 #include "chrome/common/url_constants.h"
 #include "components/web_modal/web_contents_modal_dialog_host.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/navigation_controller.h"
 #include "content/public/browser/navigation_details.h"
 #include "content/public/browser/navigation_entry.h"
 #include "content/public/browser/render_frame_host.h"
@@ skipping 180 matching lines @@
     CreateMediaRouterDialog();
     return GetMediaRouterDialog();
   }
 
   // Show the initiator holding the existing media router dialog.
   initiator_->GetDelegate()->ActivateContents(initiator_);
   return media_router_dialog;
 }
 
 WebContents* MediaRouterDialogController::ShowMediaRouterDialogForPresentation(
-    scoped_ptr<CreateSessionRequest> request) {
+    scoped_ptr<CreatePresentationSessionRequest> request) {
   DCHECK(thread_checker_.CalledOnValidThread());
 
   // Get the media router dialog for |initiator|, or create a new dialog
   // if not found.
   WebContents* media_router_dialog = GetMediaRouterDialog();
   if (!media_router_dialog) {
     CreateMediaRouterDialog();
     media_router_dialog = GetMediaRouterDialog();
     presentation_request_ = request.Pass();
     return media_router_dialog;
@@ skipping 113 matching lines @@
 
   MediaRouterUI* media_router_ui = static_cast<MediaRouterUI*>(
       media_router_dialog->GetWebUI()->GetController());
   DCHECK(media_router_ui);
   if (!media_router_ui) {
     Reset();
     return;
   }
 
   if (!presentation_request_.get()) {
-    PresentationServiceDelegateImpl::CreateForWebContents(initiator);
-    PresentationServiceDelegateImpl* delegate =
-        PresentationServiceDelegateImpl::FromWebContents(initiator);
-    CHECK(delegate);
+    // TODO(imcheng): Don't create PresentationServiceDelegateImpl if it doesn't
+    // exist (crbug.com/508695).
+    base::WeakPtr<PresentationServiceDelegateImpl> delegate =
+        PresentationServiceDelegateImpl::GetOrCreateForWebContents(initiator)
+            ->GetWeakPtr();
     media_router_ui->InitWithDefaultMediaSource(delegate);
   } else {
     media_router_ui->InitWithPresentationSessionRequest(
         initiator, presentation_request_.Pass());
   }
 }
 
 }  // namespace media_router