Let Flash join and be controlled by media session

content/browser/media/session/pepper/pepper_web_contents_observer.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/pepper/pepper_web_contents_observer.h"
+
+#include "base/feature_list.h"
+#include "base/logging.h"
+#include "content/browser/media/session/media_session.h"
+#include "content/browser/media/session/pepper/pepper_player_delegate.h"
+#include "content/common/frame_messages.h"
+#include "ipc/ipc_message_macros.h"
+#include "media/base/media_switches.h"
+
+namespace content {
+
+PepperWebContentsObserver::PepperWebContentsObserver(WebContents *web_contents)
+    : WebContentsObserver(web_contents),
+      media_session_(MediaSession::Get(web_contents)) {}
+
+PepperWebContentsObserver::~PepperWebContentsObserver() = default;
+
+void PepperWebContentsObserver::WebContentsDestroyed() {
+  for (auto& instance_player : players_map_) {
+    OnPepperStopsPlayback(instance_player.first);
+  }
+}
+
+void PepperWebContentsObserver::PepperInstanceCreated(int32_t pp_instance) {
+  DCHECK_EQ(players_map_.count(pp_instance), 0u);
+  players_map_[pp_instance].reset(new PepperPlayerDelegate(this, pp_instance));
+}
+
+void PepperWebContentsObserver::PepperInstanceDeleted(int32_t pp_instance) {
+  DCHECK_EQ(players_map_.count(pp_instance), 1u);
+
+  // Only remove the player from MediaSession once the Pepper instance
+  // is deleted.
+  if (active_players_.count(pp_instance))
+    media_session_->RemovePlayer(players_map_[pp_instance].get(), 0);
+
+  players_map_.erase(pp_instance);
+  active_players_.erase(pp_instance);
+}
+
+bool PepperWebContentsObserver::OnMessageReceived(
+    const IPC::Message& msg, RenderFrameHost* render_frame_host) {
+  if (!base::FeatureList::IsEnabled(media::kFlashJoinsMediaSession))
+    return true;
+
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_WITH_PARAM(PepperWebContentsObserver, msg,
+                                   render_frame_host)
+      IPC_MESSAGE_HANDLER(FrameHostMsg_PepperStartsPlayback,
+                          OnPepperStartsPlayback)
+      IPC_MESSAGE_HANDLER(FrameHostMsg_PepperStopsPlayback,
+                          OnPepperStopsPlayback)
+      IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+
+  return handled;
+}
+
+void PepperWebContentsObserver::OnPepperStartsPlayback(int32_t pp_instance) {
+  DCHECK_EQ(players_map_.count(pp_instance), 1u);
+
+  if (active_players_.count(pp_instance))
+    // Only add the player into MediaSession on the first time it
+    // starts playback.
+    return;
+
+  media_session_->AddPlayer(players_map_[pp_instance].get(), 0,
+                            MediaSession::Type::Content);
+  active_players_.insert(pp_instance);
+}
+
+void PepperWebContentsObserver::OnPepperStopsPlayback(int32_t pp_instance) {
+}

[mlamouri (slow - plz ping), 2016/06/24 15:33:32]

Why do you do nothing here? Actually, why does create add an entry in
`players_map_` and delete erase while start add an `active_players_` but stop
doesn't remove it?

[Zhiqiang Zhang (Slow), 2016/06/24 17:43:21]

I was thinking letting one flash join MediaSession once per lifetime and keep it
persistent until flash is deleted, but we can change this after some discussion.
This also requires some change in MediaSession. So we can put it in a follow-up
CL.

+
+}  // namespace content