Introduce AudioBufferMemoryPool to avoid thrashing on audio buffers.

media/cdm/cdm_adapter.h

Index: media/cdm/cdm_adapter.h
diff --git a/media/cdm/cdm_adapter.h b/media/cdm/cdm_adapter.h
index 837a8f3d2c473ceb816e38b07ad93b142df27847..7eca34032db8e85b622bdb9d9238c1c0f4d6bb7c 100644
--- a/media/cdm/cdm_adapter.h
+++ b/media/cdm/cdm_adapter.h
@@ -19,6 +19,7 @@
 #include "base/memory/weak_ptr.h"
 #include "base/scoped_native_library.h"
 #include "base/threading/thread.h"
+#include "media/base/audio_buffer.h"
 #include "media/base/cdm_config.h"
 #include "media/base/cdm_context.h"
 #include "media/base/cdm_factory.h"
@@ -224,6 +225,8 @@ class MEDIA_EXPORT CdmAdapter : public ContentDecryptionModule,
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
 
+  scoped_refptr<AudioBufferMemoryPool> pool_;
+
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<CdmAdapter> weak_factory_;