[Presentation API, MediaRouter] Routing from media sink selection to route creation.

chrome/browser/media/android/router/media_router_dialog_controller_android.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/android/router/media_router_dialog_controller_android.h"
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
+#include "chrome/browser/media/android/router/media_router_android.h"
+#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/sessions/session_tab_helper.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_delegate.h"
 #include "jni/ChromeMediaRouterDialogController_jni.h"
 
 DEFINE_WEB_CONTENTS_USER_DATA_KEY(
     media_router::MediaRouterDialogControllerAndroid);
 
+using base::android::ConvertJavaStringToUTF8;
 using content::WebContents;
 
 namespace media_router {
 
 // static
 MediaRouterDialogControllerAndroid*
 MediaRouterDialogControllerAndroid::GetOrCreateForWebContents(
     WebContents* web_contents) {
   DCHECK(web_contents);
   // This call does nothing if the controller already exists.
   MediaRouterDialogControllerAndroid::CreateForWebContents(web_contents);
   return MediaRouterDialogControllerAndroid::FromWebContents(web_contents);
 }
 
+void MediaRouterDialogControllerAndroid::OnSinkSelected(
+    JNIEnv* env, jobject obj, jstring jsink_id) {
+  scoped_ptr<CreatePresentationSessionRequest>
+      request(PassPresentationRequest());
+  DCHECK(request);

[Wez, 2015/08/18 21:50:08]

You're dereferencing |request| immediately after this, so there's no need to
DCHECK here.

[whywhat, 2015/08/19 13:04:29]

Done.

+
+  const std::string& source_id = request->media_source().id();
+  const GURL& origin = request->frame_url().GetOrigin();
+
+  std::vector<MediaRouteResponseCallback> route_response_callbacks;
+  route_response_callbacks.push_back(
+      base::Bind(&CreatePresentationSessionRequest::HandleRouteResponse,
+                 base::Passed(&request)));
+
+  MediaRouter* router = static_cast<MediaRouterAndroid*>(

[Wez, 2015/08/18 21:50:08]

Why are you static-casting to MediaRouterAndroid* if you're going to assign it
to a MediaRouter*..?

+      MediaRouterFactory::GetApiForBrowserContext(
+          initiator()->GetBrowserContext()));
+  DCHECK(router);

[Wez, 2015/08/18 21:50:08]

Same here.

[whywhat, 2015/08/19 13:04:29]

Done.

+  router->CreateRoute(source_id,
+                      ConvertJavaStringToUTF8(env, jsink_id),
+                      origin,
+                      SessionTabHelper::IdForTab(initiator()),
+                      route_response_callbacks);
+}
+
+void MediaRouterDialogControllerAndroid::OnDialogDismissed(
+    JNIEnv* env, jobject obj) {
+  scoped_ptr<CreatePresentationSessionRequest> request(
+      PassPresentationRequest());
+
+  // If OnDialogDismissed is called after OnSinkSelected, do nothing.
+  if (!request)
+    return;
+
+  request->MaybeInvokeErrorCallback(content::PresentationError(
+      content::PRESENTATION_ERROR_SESSION_REQUEST_CANCELLED,
+      "The device picker dialog has been dismissed"));

[Wez, 2015/08/18 21:50:08]

Shouldn't this be a localizable string?

[whywhat, 2015/08/19 13:04:29]

This is an error message returned to the web developer along with the error code
so I don't think so.

+}
+
 MediaRouterDialogControllerAndroid::MediaRouterDialogControllerAndroid(
     WebContents* web_contents)
     : MediaRouterDialogController(web_contents) {
   JNIEnv* env = base::android::AttachCurrentThread();
   java_dialog_controller_.Reset(Java_ChromeMediaRouterDialogController_create(
       env,
       reinterpret_cast<jlong>(this),
       base::android::GetApplicationContext()));
 }
 
 // static
 bool MediaRouterDialogControllerAndroid::Register(JNIEnv* env) {
   bool ret = RegisterNativesImpl(env);
-  // No native calls to register yet.
-  // DCHECK(g_ChromeMediaRouterDialogController_clazz);
+  DCHECK(g_ChromeMediaRouterDialogController_clazz);

[Wez, 2015/08/18 21:50:08]

I searched about for some relationship between this and RegisterNativesImpl but
I can't even find references to the _clazz, so I can't answer my own questions:
Why do we DCHECK the _clazz but ignore the return-code of RegisterNativesImpl?
What is it that calling code will do if Register() returns false? Is there a
meaningful fallback, or in practice does it mean that Things Went Horribly
Wrong? If the latter, then why not CHECK here?

[whywhat, 2015/08/19 13:04:29]

It seems like noone is doing this check any longer in any other Register
methods.
The RegisterNativesImpl is auto generated from "native" methods in the Java
file. It's defined in the jni/ChromeMediaRouterDialogController_jni.h
If it returns false, it means something did went horribly wrong and loading the
Chrome's native .so library will fail, so the app will crash on startup.

   return ret;
 }
 
 MediaRouterDialogControllerAndroid::~MediaRouterDialogControllerAndroid() {
 }
 
 void MediaRouterDialogControllerAndroid::CreateMediaRouterDialog() {
   JNIEnv* env = base::android::AttachCurrentThread();
 
-  scoped_ptr<CreatePresentationSessionRequest> presentation_request(
-      PassPresentationRequest());
-
   ScopedJavaLocalRef<jstring> jsource_urn =
       base::android::ConvertUTF8ToJavaString(
-          env, presentation_request->media_source().id());
+          env, GetPresentationRequest()->media_source().id());
 
   Java_ChromeMediaRouterDialogController_createDialog(
       env, java_dialog_controller_.obj(), jsource_urn.obj());
 }
 
 void MediaRouterDialogControllerAndroid::CloseMediaRouterDialog() {
   JNIEnv* env = base::android::AttachCurrentThread();
 
   Java_ChromeMediaRouterDialogController_closeDialog(
       env, java_dialog_controller_.obj());
 }
 
 bool MediaRouterDialogControllerAndroid::IsShowingMediaRouterDialog() const {
   JNIEnv* env = base::android::AttachCurrentThread();
   return Java_ChromeMediaRouterDialogController_isShowingDialog(
       env, java_dialog_controller_.obj());
 }
 
 }  // namespace media_router