Fix a crash that MediaPlayerAndroid weak_ptr is incorrectly used across thread

media/base/android/media_player_listener.cc

Index: media/base/android/media_player_listener.cc
diff --git a/media/base/android/media_player_listener.cc b/media/base/android/media_player_listener.cc
index 861a34f7b0b3a636540b29b5ba0cf13fbd52db8a..60292ef92473e1e7d768b9b69823e7c7a2b36583 100644
--- a/media/base/android/media_player_listener.cc
+++ b/media/base/android/media_player_listener.cc
@@ -18,7 +18,7 @@ using base::android::ScopedJavaLocalRef;
 
 namespace media {
 
-MediaPlayerListener::MediaPlayerListener(
+MediaPlayerListenerProxy::MediaPlayerListenerProxy(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
     base::WeakPtr<MediaPlayerAndroid> media_player)
     : task_runner_(task_runner),
@@ -27,6 +27,100 @@ MediaPlayerListener::MediaPlayerListener(
   DCHECK(media_player_);
 }
 
+void MediaPlayerListenerProxy::OnMediaError(int error_type) {
+  if (!task_runner_->BelongsToCurrentThread()) {
+    task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&MediaPlayerListenerProxy::OnMediaError, this, error_type));
+    return;
+  }
+
+  if (media_player_)
+    media_player_->OnMediaError(error_type);
+}
+
+void MediaPlayerListenerProxy::OnVideoSizeChanged(int width, int height) {
+  if (!task_runner_->BelongsToCurrentThread()) {
+    task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&MediaPlayerListenerProxy::OnVideoSizeChanged,
+                   this, width, height));
+    return;
+  }
+
+  if (media_player_)
+    media_player_->OnVideoSizeChanged(width, height);
+}
+
+void MediaPlayerListenerProxy::OnBufferingUpdate(int percent) {
+  if (!task_runner_->BelongsToCurrentThread()) {
+    task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&MediaPlayerListenerProxy::OnBufferingUpdate,
+                   this, percent));
+    return;
+  }
+
+  if (media_player_)
+    media_player_->OnBufferingUpdate(percent);
+}
+
+void MediaPlayerListenerProxy::OnPlaybackComplete() {
+  if (!task_runner_->BelongsToCurrentThread()) {
+    task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&MediaPlayerListenerProxy::OnPlaybackComplete, this));
+    return;
+  }
+
+  if (media_player_)
+    media_player_->OnPlaybackComplete();
+}
+
+void MediaPlayerListenerProxy::OnSeekComplete() {
+  if (!task_runner_->BelongsToCurrentThread()) {
+    task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&MediaPlayerListenerProxy::OnSeekComplete, this));
+    return;
+  }
+
+  if (media_player_)
+    media_player_->OnSeekComplete();
+}
+
+void MediaPlayerListenerProxy::OnMediaPrepared() {
+  if (!task_runner_->BelongsToCurrentThread()) {
+    task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&MediaPlayerListenerProxy::OnMediaPrepared, this));
+    return;
+  }
+
+  if (media_player_)
+    media_player_->OnMediaPrepared();
+}
+
+void MediaPlayerListenerProxy::OnMediaInterrupted() {
+  if (!task_runner_->BelongsToCurrentThread()) {
+    task_runner_->PostTask(
+        FROM_HERE,
+        base::Bind(&MediaPlayerListenerProxy::OnMediaInterrupted, this));
+    return;
+  }
+
+  if (media_player_)
+    media_player_->OnMediaInterrupted();
+}
+
+MediaPlayerListenerProxy::~MediaPlayerListenerProxy() {}
+
+MediaPlayerListener::MediaPlayerListener(
+    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+    base::WeakPtr<MediaPlayerAndroid> media_player)
+    : proxy_(new MediaPlayerListenerProxy(task_runner, media_player)) {
+}
+
 MediaPlayerListener::~MediaPlayerListener() {}
 
 void MediaPlayerListener::CreateMediaPlayerListener(
@@ -39,7 +133,6 @@ void MediaPlayerListener::CreateMediaPlayerListener(
   }
 }
 
-
 void MediaPlayerListener::ReleaseMediaPlayerListenerResources() {
   JNIEnv* env = AttachCurrentThread();
   CHECK(env);
@@ -52,45 +145,37 @@ void MediaPlayerListener::ReleaseMediaPlayerListenerResources() {
 
 void MediaPlayerListener::OnMediaError(
     JNIEnv* /* env */, jobject /* obj */, jint error_type) {
-  task_runner_->PostTask(FROM_HERE, base::Bind(
-      &MediaPlayerAndroid::OnMediaError, media_player_, error_type));
+  proxy_->OnMediaError(error_type);
 }
 
 void MediaPlayerListener::OnVideoSizeChanged(
     JNIEnv* /* env */, jobject /* obj */, jint width, jint height) {
-  task_runner_->PostTask(FROM_HERE, base::Bind(
-      &MediaPlayerAndroid::OnVideoSizeChanged, media_player_,
-      width, height));
+  proxy_->OnVideoSizeChanged(width, height);
 }
 
 void MediaPlayerListener::OnBufferingUpdate(
     JNIEnv* /* env */, jobject /* obj */, jint percent) {
-  task_runner_->PostTask(FROM_HERE, base::Bind(
-      &MediaPlayerAndroid::OnBufferingUpdate, media_player_, percent));
+  proxy_->OnBufferingUpdate(percent);
 }
 
 void MediaPlayerListener::OnPlaybackComplete(
     JNIEnv* /* env */, jobject /* obj */) {
-  task_runner_->PostTask(FROM_HERE, base::Bind(
-      &MediaPlayerAndroid::OnPlaybackComplete, media_player_));
+  proxy_->OnPlaybackComplete();
 }
 
 void MediaPlayerListener::OnSeekComplete(
     JNIEnv* /* env */, jobject /* obj */) {
-  task_runner_->PostTask(FROM_HERE, base::Bind(
-      &MediaPlayerAndroid::OnSeekComplete, media_player_));
+  proxy_->OnSeekComplete();
 }
 
 void MediaPlayerListener::OnMediaPrepared(
     JNIEnv* /* env */, jobject /* obj */) {
-  task_runner_->PostTask(FROM_HERE, base::Bind(
-      &MediaPlayerAndroid::OnMediaPrepared, media_player_));
+  proxy_->OnMediaPrepared();
 }
 
 void MediaPlayerListener::OnMediaInterrupted(
     JNIEnv* /* env */, jobject /* obj */) {
-  task_runner_->PostTask(FROM_HERE, base::Bind(
-      &MediaPlayerAndroid::OnMediaInterrupted, media_player_));
+  proxy_->OnMediaInterrupted();
 }
 
 bool MediaPlayerListener::RegisterMediaPlayerListener(JNIEnv* env) {