Makes AudioOutputProxy -> AudioOutputDispatcher reference weak.

media/audio/audio_output_proxy.h

Index: media/audio/audio_output_proxy.h
diff --git a/media/audio/audio_output_proxy.h b/media/audio/audio_output_proxy.h
index 0b358087348f307db5c98da281417a7048e66d1c..16a062824ea55d81aaf86c00dea8907d9307ef3f 100644
--- a/media/audio/audio_output_proxy.h
+++ b/media/audio/audio_output_proxy.h
@@ -7,6 +7,7 @@
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
 #include "media/audio/audio_io.h"
 #include "media/base/audio_parameters.h"
@@ -28,7 +29,7 @@ class MEDIA_EXPORT AudioOutputProxy
     public NON_EXPORTED_BASE(base::NonThreadSafe) {
  public:
   // Caller keeps ownership of |dispatcher|.
-  explicit AudioOutputProxy(AudioOutputDispatcher* dispatcher);
+  explicit AudioOutputProxy(base::WeakPtr<AudioOutputDispatcher> dispatcher);
 
   // AudioOutputStream interface.
   bool Open() override;
@@ -39,7 +40,7 @@ class MEDIA_EXPORT AudioOutputProxy
   void Close() override;
 
   AudioOutputDispatcher* get_dispatcher_for_testing() const {
-    return dispatcher_;
+    return dispatcher_.get();
   }
 
  private:
@@ -54,7 +55,7 @@ class MEDIA_EXPORT AudioOutputProxy
 
   ~AudioOutputProxy() override;
 
-  AudioOutputDispatcher* dispatcher_;
+  base::WeakPtr<AudioOutputDispatcher> dispatcher_;
   State state_;
 
   // Need to save volume here, so that we can restore it in case the stream