Refactor MediaSourceDelegate destruction.

content/renderer/media/android/webmediaplayer_android.cc

Index: content/renderer/media/android/webmediaplayer_android.cc
diff --git a/content/renderer/media/android/webmediaplayer_android.cc b/content/renderer/media/android/webmediaplayer_android.cc
index ea6ba1f0d538dcbb96d046e39c9af674aca353da..155eea86d912b4783858385ae90d1a8b95bb0d3f 100644
--- a/content/renderer/media/android/webmediaplayer_android.cc
+++ b/content/renderer/media/android/webmediaplayer_android.cc
@@ -210,6 +210,16 @@ WebMediaPlayerAndroid::~WebMediaPlayerAndroid() {
     delegate_->PlayerGone(this);
 
   stream_texture_factory_->RemoveObserver(this);
+
+  if (media_source_delegate_) {
+    // Part of |media_source_delegate_| needs to be stopped on the media thread.
+    // Wait until |media_source_delegate_| is fully stopped before tearing
+    // down other objects.
+    base::WaitableEvent waiter(false, false);
+    media_source_delegate_->Stop(
+        base::Bind(&base::WaitableEvent::Signal, base::Unretained(&waiter)));
+    waiter.Wait();
+  }
 }
 
 void WebMediaPlayerAndroid::load(LoadType load_type,