Add support for encrypted WebM files as defined in the RFC.

webkit/media/webmediaplayer_impl.cc

Index: webkit/media/webmediaplayer_impl.cc
diff --git a/webkit/media/webmediaplayer_impl.cc b/webkit/media/webmediaplayer_impl.cc
index 3120d9cf2f0a194ced15a2fd26b6175aee00cda4..d61729bb804b0b2c487fd7e3c2a38386baa0db1b 100644
--- a/webkit/media/webmediaplayer_impl.cc
+++ b/webkit/media/webmediaplayer_impl.cc
@@ -21,7 +21,7 @@
 #include "media/base/media_switches.h"
 #include "media/base/pipeline.h"
 #include "media/base/video_frame.h"
-#include "media/crypto/aes_decryptor.h"
+#include "media/crypto/hmac_aes_decryptor.h"
 #include "media/filters/audio_renderer_impl.h"
 #include "media/filters/video_renderer_base.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebVideoFrame.h"
@@ -155,7 +155,7 @@ WebMediaPlayerImpl::WebMediaPlayerImpl(
   filter_collection_->AddAudioRenderer(
       new media::AudioRendererImpl(new media::NullAudioSink()));
 
-  decryptor_.reset(new media::AesDecryptor());
+  decryptor_.reset(new media::HmacAesDecryptor());
 }
 
 WebMediaPlayerImpl::~WebMediaPlayerImpl() {