Migrate AudioFocusChangeListener to browser and always send GAIN

content/browser/media/android/audio_focus_manager.h

+// 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.
+
+#ifndef CONTENT_BROWSER_MEDIA_ANDROID_AUDIO_FOCUS_MANAGER_H_
+#define CONTENT_BROWSER_MEDIA_ANDROID_AUDIO_FOCUS_MANAGER_H_
+
+#include <jni.h>
+
+#include "base/android/scoped_java_ref.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace content {
+class BrowserMediaPlayerManager;
+
+class AudioFocusManager {
+ public:
+  AudioFocusManager(
+      const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+      base::WeakPtr<BrowserMediaPlayerManager> manager);
+  ~AudioFocusManager();
+
+  static bool RegisterAudioFocusManager(JNIEnv* env);
+
+  // Called by AudioFocusManager.java.
+  void OnMediaInterrupted(JNIEnv*, jobject, jint player_id);
+
+  // Called by browser_media_player_manager.cc
+  void RequestAudioFocus(int player_id);
+  void AbandonAudioFocus(int player_id);
+
+ private:
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
+  base::WeakPtr<BrowserMediaPlayerManager> manager_;
+
+  base::android::ScopedJavaGlobalRef<jobject> j_audio_focus_manager_;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioFocusManager);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_MEDIA_ANDROID_AUDIO_FOCUS_MANAGER_H_