[Presentation API / Media Router] Clean up default pres URL logic.

chrome/browser/media/android/router/media_router_dialog_controller_android.cc

Index: chrome/browser/media/android/router/media_router_dialog_controller_android.cc
diff --git a/chrome/browser/media/android/router/media_router_dialog_controller_android.cc b/chrome/browser/media/android/router/media_router_dialog_controller_android.cc
index e0e05336efbf653efbb9702f6b065fa5cf047844..4a61bd4fd13e763ef786cf6dddf390fcb9818771 100644
--- a/chrome/browser/media/android/router/media_router_dialog_controller_android.cc
+++ b/chrome/browser/media/android/router/media_router_dialog_controller_android.cc
@@ -10,6 +10,8 @@
 #include "chrome/browser/media/router/media_router.h"
 #include "chrome/browser/media/router/media_router_factory.h"
 #include "chrome/browser/media/router/media_source.h"
+#include "chrome/browser/media/router/media_source_helper.h"
+#include "chrome/browser/media/router/presentation_request.h"
 #include "chrome/browser/sessions/session_tab_helper.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
@@ -36,16 +38,20 @@ MediaRouterDialogControllerAndroid::GetOrCreateForWebContents(
 
 void MediaRouterDialogControllerAndroid::OnSinkSelected(
     JNIEnv* env, jobject obj, jstring jsink_id) {
-  scoped_ptr<CreatePresentationSessionRequest>
-      request(TakePresentationRequest());
+  scoped_ptr<CreatePresentationSessionRequest> create_session_request(
+      TakePresentationRequest());
 
-  const std::string& source_id = request->media_source().id();
-  const GURL& origin = request->frame_url().GetOrigin();
+  const PresentationRequest& presentation_request =
+      create_session_request->presentation_request();
+  const MediaSource::Id source_id(

[mark a. foltz, 2015/10/20 20:15:25]

I actually preferred the previous code, where you call
PresentationRequest::media_source() to get the corresponding source.  What
motivates this change?

[imcheng, 2015/10/24 00:41:19]

It's because now the CreateSessionRequest now holds a PresentationRequest which
holds a presentation url. I will add a helper method to return the MediaSource
to reduce the clutter here?

+      MediaSourceForPresentationUrl(presentation_request.presentation_url())
+          .id());
+  const GURL origin(presentation_request.frame_url().GetOrigin());
 
   std::vector<MediaRouteResponseCallback> route_response_callbacks;
   route_response_callbacks.push_back(
       base::Bind(&CreatePresentationSessionRequest::HandleRouteResponse,
-                 base::Passed(&request)));
+                 base::Passed(&create_session_request)));
 
   MediaRouter* router = MediaRouterFactory::GetApiForBrowserContext(
       initiator()->GetBrowserContext());
@@ -107,8 +113,10 @@ MediaRouterDialogControllerAndroid::~MediaRouterDialogControllerAndroid() {
 void MediaRouterDialogControllerAndroid::CreateMediaRouterDialog() {
   JNIEnv* env = base::android::AttachCurrentThread();
 
+  const std::string& presentation_url =
+      create_session_request()->presentation_request().presentation_url();
   const MediaSource::Id& media_source_id =
-      presentation_request()->media_source().id();
+      MediaSourceForPresentationUrl(presentation_url).id();
   ScopedJavaLocalRef<jstring> jsource_urn =
       base::android::ConvertUTF8ToJavaString(env, media_source_id);