diff --git a/content/media/plugins/MediaPluginDecoder.cpp b/content/media/plugins/MediaPluginDecoder.cpp
index 8751d826446f..df20598c5e34 100644
--- a/content/media/plugins/MediaPluginDecoder.cpp
+++ b/content/media/plugins/MediaPluginDecoder.cpp
@@ -16,7 +16,7 @@ MediaPluginDecoder::MediaPluginDecoder(const nsACString& aType) : mType(aType)
 
 MediaDecoderStateMachine* MediaPluginDecoder::CreateStateMachine()
 {
-  return new MediaDecoderStateMachine(this, new MediaPluginReader(this));
+  return new MediaDecoderStateMachine(this, new MediaPluginReader(this, mType));
 }
 
 } // namespace mozilla
diff --git a/content/media/plugins/MediaPluginReader.cpp b/content/media/plugins/MediaPluginReader.cpp
index aef9e90758de..b8bec26a2507 100644
--- a/content/media/plugins/MediaPluginReader.cpp
+++ b/content/media/plugins/MediaPluginReader.cpp
@@ -15,8 +15,10 @@
 
 namespace mozilla {
 
-MediaPluginReader::MediaPluginReader(AbstractMediaDecoder *aDecoder) :
+MediaPluginReader::MediaPluginReader(AbstractMediaDecoder *aDecoder,
+                                     const nsACString& aContentType) :
   MediaDecoderReader(aDecoder),
+  mType(aContentType),
   mPlugin(NULL),
   mHasAudio(false),
   mHasVideo(false),
@@ -24,7 +26,6 @@ MediaPluginReader::MediaPluginReader(AbstractMediaDecoder *aDecoder) :
   mAudioSeekTimeUs(-1),
   mLastVideoFrame(NULL)
 {
-  static_cast<MediaPluginDecoder *>(aDecoder)->GetContentType(mType);
 }
 
 MediaPluginReader::~MediaPluginReader()
diff --git a/content/media/plugins/MediaPluginReader.h b/content/media/plugins/MediaPluginReader.h
index f86f7f1fef3d..ea44397fc9e6 100644
--- a/content/media/plugins/MediaPluginReader.h
+++ b/content/media/plugins/MediaPluginReader.h
@@ -11,6 +11,8 @@
 
 #include "MPAPI.h"
 
+class nsACString;
+
 namespace mozilla {
 
 class AbstractMediaDecoder;
@@ -27,7 +29,8 @@ class MediaPluginReader : public MediaDecoderReader
   int64_t mAudioSeekTimeUs;
   VideoData *mLastVideoFrame;
 public:
-  MediaPluginReader(AbstractMediaDecoder* aDecoder);
+  MediaPluginReader(AbstractMediaDecoder* aDecoder,
+                    const nsACString& aContentType);
   ~MediaPluginReader();
 
   virtual nsresult Init(MediaDecoderReader* aCloneDonor);