Add render-side manager for MediaSession

content/renderer/media/android/renderer_media_session_manager.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 "content/renderer/media/android/renderer_media_session_manager.h"
+
+#include "base/logging.h"
+#include "content/renderer/media/android/webmediasession_android.h"
+
+namespace content {
+
+static const int kDefaultMediaSessionID = 0;
+
+RendererMediaSessionManager::RendererMediaSessionManager(
+    RenderFrame* render_frame)
+    : RenderFrameObserver(render_frame),
+      next_session_id_(kDefaultMediaSessionID + 1) {}
+
+RendererMediaSessionManager::~RendererMediaSessionManager() {
+  DCHECK(sessions_.empty())
+      << "RendererMediaSessionManager is owned by RenderFrameImpl and is "
+         "destroyed only after all media sessions are destroyed.";
+}
+
+int RendererMediaSessionManager::RegisterMediaSession(
+    WebMediaSessionAndroid* session) {
+  sessions_[next_session_id_] = session;
+  return next_session_id_++;
+}
+
+void RendererMediaSessionManager::UnregisterMediaSession(int session_id) {
+  sessions_.erase(session_id);
+}
+
+}  // namespace content