Bug 1421134. P1 - default MediaCacheStream::mCurrentMode to MODE_METADATA. r=bechen,gerald

We always read metadata when decoding starts. This allows us to remove the call
to mResource->SetReadMode(MediaCacheStream::MODE_METADATA) in ChannelMediaDecoder::Load().

MozReview-Commit-ID: AQMq4HxDZdT

--HG--
extra : rebase_source : 141c43bb93f274d8320a270b5c7289bd1eab134d
extra : source : 7de3d88ddb5c99352f4b5bd0b5e648a52a4a67a5

dom/media/BaseMediaResource.h

@@ -64,7 +64,7 @@ public:
   // Resume any downloads that have been suspended.
   virtual void Resume() = 0;
 
-  // The mode is initially MODE_PLAYBACK.
+  // The mode is initially MODE_METADATA.
   virtual void SetReadMode(MediaCacheStream::ReadMode aMode) = 0;
 
   // Returns true if the resource can be seeked to unbuffered ranges, i.e.

dom/media/ChannelMediaDecoder.cpp

@@ -255,9 +255,6 @@ ChannelMediaDecoder::Load(nsIChannel* aChannel,
   rv = mResource->Open(aStreamListener);
   NS_ENSURE_SUCCESS(rv, rv);
 
-  // Set mode to METADATA since we are about to read metadata.
-  mResource->SetReadMode(MediaCacheStream::MODE_METADATA);
-
   SetStateMachine(CreateStateMachine());
   NS_ENSURE_TRUE(GetStateMachine(), NS_ERROR_FAILURE);
 

dom/media/MediaCache.cpp

@@ -507,7 +507,6 @@ MediaCacheStream::MediaCacheStream(ChannelMediaResource* aClient,
   , mStreamOffset(0)
   , mPlaybackBytesPerSecond(10000)
   , mPinCount(0)
-  , mCurrentMode(MODE_PLAYBACK)
   , mMetadataInPartialBlockBuffer(false)
   , mIsPrivateBrowsing(aIsPrivateBrowsing)
 {

dom/media/MediaCache.h

@@ -523,7 +523,7 @@ private:
   // when mDidNotifyDataEnded is true.
   nsresult          mNotifyDataEndedStatus;
   // The last reported read mode
-  ReadMode          mCurrentMode;
+  ReadMode mCurrentMode = MODE_METADATA;
   // True if some data in mPartialBlockBuffer has been read as metadata
   bool              mMetadataInPartialBlockBuffer;
   // The load ID of the current channel. Used to check whether the data is