Introduce AudioBufferMemoryPool to avoid thrashing on audio buffers.

content/renderer/pepper/content_decryptor_delegate.h

Index: content/renderer/pepper/content_decryptor_delegate.h
diff --git a/content/renderer/pepper/content_decryptor_delegate.h b/content/renderer/pepper/content_decryptor_delegate.h
index 695aa2e4a4f96b7e1f767998db4bfe5220c972b5..fdd16b1da185bd2e7f4ddd5eb5c09c0b6c7d3a16 100644
--- a/content/renderer/pepper/content_decryptor_delegate.h
+++ b/content/renderer/pepper/content_decryptor_delegate.h
@@ -18,6 +18,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
+#include "media/base/audio_buffer.h"
 #include "media/base/cdm_promise.h"
 #include "media/base/cdm_promise_adapter.h"
 #include "media/base/cdm_session_tracker.h"
@@ -243,6 +244,8 @@ class ContentDecryptorDelegate {
 
   media::CdmSessionTracker cdm_session_tracker_;
 
+  scoped_refptr<media::AudioBufferMemoryPool> pool_;
+
   base::WeakPtr<ContentDecryptorDelegate> weak_this_;
   base::WeakPtrFactory<ContentDecryptorDelegate> weak_ptr_factory_;