Adding new media controls to MediaNotification

content/browser/media/session/media_session_service_impl.cc

 // Copyright 2016 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 "content/browser/media/session/media_session_service_impl.h"
 
 #include "content/browser/media/session/media_metadata_sanitizer.h"
 #include "content/browser/media/session/media_session_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/web_contents.h"
 
 namespace content {
 
 MediaSessionServiceImpl::MediaSessionServiceImpl(
     RenderFrameHost* render_frame_host)
-    : render_frame_host_(render_frame_host) {}
+    : render_frame_host_(render_frame_host) {
+  if (MediaSessionImpl* session = GetMediaSession())
+    session->SetMediaSessionService(this);
+}
 
-MediaSessionServiceImpl::~MediaSessionServiceImpl() = default;
+MediaSessionServiceImpl::~MediaSessionServiceImpl() {
+  if (MediaSessionImpl* session = GetMediaSession())

[whywhat, 2016/10/28 16:10:23]

nit: can this be null here and below?
I'd avoid initialization in the if () condition as it may confuse readers
(although it doesn't seem to be forbidden in the style guide and there're about
250 existing cases I found:
https://cs.chromium.org/search/?q=file:%5C.cc+if%5Cs%5C(%5B%5E)%22%5D*?%5Cs%3...

[Zhiqiang Zhang (Slow), 2016/11/01 15:24:15]

Yes, currently we only bind the top-level frame service with MediaSession, so
GetMediaSession() will return null for child frames.
Done for the style.

Actually I should also check if |this| == session->service_ here, fixed in the
new patch.

+    session->SetMediaSessionService(nullptr);
+}
 
 // static
 void MediaSessionServiceImpl::Create(
     RenderFrameHost* render_frame_host,
     blink::mojom::MediaSessionServiceRequest request) {
   MediaSessionServiceImpl* impl =
       new MediaSessionServiceImpl(render_frame_host);
   impl->Bind(std::move(request));
 }
 
 void MediaSessionServiceImpl::SetClient(
     blink::mojom::MediaSessionClientPtr client) {
   client_ = std::move(client);
 }
 
 void MediaSessionServiceImpl::SetMetadata(
     const base::Optional<content::MediaMetadata>& metadata) {
   // When receiving a MediaMetadata, the browser process can't trust that it is
   // coming from a known and secure source. It must be processed accordingly.
   if (metadata.has_value() &&
       !MediaMetadataSanitizer::CheckSanity(metadata.value())) {
     render_frame_host_->GetProcess()->ShutdownForBadMessage(
         RenderProcessHost::CrashReportMode::GENERATE_CRASH_DUMP);
     return;
   }
 
-  WebContentsImpl* contents = static_cast<WebContentsImpl*>(
-      WebContentsImpl::FromRenderFrameHost(render_frame_host_));
-  if (contents)
-    MediaSessionImpl::Get(contents)->SetMetadata(metadata);
+  if (MediaSessionImpl* session = GetMediaSession())
+    session->SetMetadata(metadata);
 }
 
 void MediaSessionServiceImpl::EnableAction(
     blink::mojom::MediaSessionAction action) {
-  // TODO(zqzhang): Plumb this signal to Java. See https://crbug.com/656563
-  NOTIMPLEMENTED();
+  if (MediaSessionImpl* session = GetMediaSession())
+    session->OnMediaSessionEnabledAction(action);
 }
 
 void MediaSessionServiceImpl::DisableAction(
     blink::mojom::MediaSessionAction action) {
-  // TODO(zqzhang): Plumb this signal to Java. See https://crbug.com/656563
-  NOTIMPLEMENTED();
+  if (MediaSessionImpl* session = GetMediaSession())
+    session->OnMediaSessionDisabledAction(action);
+}
+
+MediaSessionImpl* MediaSessionServiceImpl::GetMediaSession() {
+  WebContentsImpl* contents = static_cast<WebContentsImpl*>(
+      WebContentsImpl::FromRenderFrameHost(render_frame_host_));
+  if (!contents)
+    return nullptr;
+  if (render_frame_host_ != contents->GetMainFrame())
+    return nullptr;
+  return MediaSessionImpl::Get(contents);
 }
 
 void MediaSessionServiceImpl::Bind(
     blink::mojom::MediaSessionServiceRequest request) {
   binding_.reset(new mojo::Binding<blink::mojom::MediaSessionService>(
       this, std::move(request)));
 }
 
 }  // namespace content