Bug Fix: WebMediaPlayerMS Crashes

content/renderer/media/webmediaplayer_ms_compositor.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_RENDERER_MEDIA_WEBMEDIAPLAYER_MS_COMPOSITOR_H
 #define CONTENT_RENDERER_MEDIA_WEBMEDIAPLAYER_MS_COMPOSITOR_H
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 30 matching lines @@
 // This class is designed to handle the work load on compositor thread for
 // WebMediaPlayerMS. It will be instantiated on the main thread, but destroyed
 // on the compositor thread.
 //
 // WebMediaPlayerMSCompositor utilizes VideoRendererAlgorithm to store the
 // incoming frames and select the best frame for rendering to maximize the
 // smoothness, if REFERENCE_TIMEs are populated for incoming VideoFrames.
 // Otherwise, WebMediaPlayerMSCompositor will simply store the most recent
 // frame, and submit it whenever asked by the compositor.
 class CONTENT_EXPORT WebMediaPlayerMSCompositor
-    : public NON_EXPORTED_BASE(cc::VideoFrameProvider) {
+    : public NON_EXPORTED_BASE(cc::VideoFrameProvider),
+      public NON_EXPORTED_BASE(
+          base::SupportsWeakPtr<WebMediaPlayerMSCompositor>) {

[DaleCurtis, 2016/01/07 21:05:46]

Instead of using SupportsWeakPtr, can you just add a WeakFactory member? That's
the preferred pattern for small use cases like this. It prevents external
classes from taking a weakptr unnecessarily.

[qiangchen, 2016/01/08 17:10:12]

Done.

  public:
   // This |url| represents the media stream we are rendering. |url| is used to
   // find out what web stream this WebMediaPlayerMSCompositor is playing, and
   // together with flag "--disable-rtc-smoothness-algorithm" determine whether
   // we enable algorithm or not.
   WebMediaPlayerMSCompositor(
       const scoped_refptr<base::SingleThreadTaskRunner>& compositor_task_runner,
       const blink::WebURL& url,
       const base::WeakPtr<WebMediaPlayerMS>& player);
 
@@ skipping 83 matching lines @@
 
   std::map<base::TimeDelta, base::TimeTicks> timestamps_to_clock_times_;
 
   // |current_frame_lock_| protects |current_frame_used_by_compositor_|,
   // |current_frame_|, and |rendering_frame_buffer_|.
   base::Lock current_frame_lock_;
 };
 }
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBMEDIAPLAYER_MS_COMPOSITOR_H