Refactor MSE implementation on Android to simplify the logic and improve the performance

media/base/android/media_decoder_job.h

Index: media/base/android/media_decoder_job.h
diff --git a/media/base/android/media_decoder_job.h b/media/base/android/media_decoder_job.h
index 9dbbd00fceaba8c1a222fabfd6e95c0fce8749b1..6542ba41f0b193fe1943ee09d68d34842aaaa19b 100644
--- a/media/base/android/media_decoder_job.h
+++ b/media/base/android/media_decoder_job.h
@@ -10,6 +10,7 @@
 #include "base/time/time.h"
 #include "media/base/android/demuxer_stream_player_params.h"
 #include "media/base/android/media_codec_bridge.h"
+#include "ui/gl/android/scoped_java_surface.h"
 
 namespace base {
 class SingleThreadTaskRunner;
@@ -17,6 +18,8 @@ class SingleThreadTaskRunner;
 
 namespace media {
 
+class MediaDrmBridge;
+
 // Class for managing all the decoding tasks. Each decoding task will be posted
 // onto the same thread. The thread will be stopped once Stop() is called.
 // Data is stored in 2 chunks. When new data arrives, it is always stored in
@@ -56,8 +59,8 @@ class MediaDecoderJob {
   //
   // Returns true if the next decode was started and |callback| will be
   // called when the decode operation is complete.
-  // Returns false if a config change is needed. |callback| is ignored
-  // and will not be called.
+  // Returns false if |media_codec_bridge_| cannot be created. |callback| is
+  // ignored and will not be called.
   bool Decode(base::TimeTicks start_time_ticks,
               base::TimeDelta start_presentation_timestamp,
               const DecoderCallback& callback);
@@ -72,25 +75,42 @@ class MediaDecoderJob {
   // reflects whether data was actually decoded or the decode terminated early.
   void StopDecode();
 
-  // Flush the decoder.
+  // Flushes the decoder and abandons all the data that is being decoded.
   void Flush();
 
   // Enter prerolling state. The job must not currently be decoding.
   void BeginPrerolling(base::TimeDelta preroll_timestamp);
 
-  bool prerolling() const { return prerolling_; }
+  // Releases all the decoder resources as the current tab is going background.
+  virtual void ReleaseDecoderResources();
+
+  // Sets the demuxer configs. Returns true if configs has changed, or false
+  // otherwise.
+  virtual bool SetDemuxerConfigs(const DemuxerConfigs& configs);
+
+  // Returns whether the decoder has finished decoding all the data.
+  bool OutputEOSReached() const;
+
+  // Returns true if the audio/video stream is available, implemented by child
+  // classes.
+  virtual bool HasStream() const = 0;
 
   bool is_decoding() const { return !decode_cb_.is_null(); }
 
-  bool is_requesting_demuxer_data() const {
-    return is_requesting_demuxer_data_;
-  }
+  void set_drm_bridge(MediaDrmBridge* drm_bridge) { drm_bridge_ = drm_bridge; }
+
+  bool is_content_encrypted() const { return is_content_encrypted_; }
 
  protected:
+  // Creates a new MediaDecoderJob instance.
+  // |decoder_task_runner| - Thread on which the decoder task will run.
+  // |request_data_cb| - Callback to request more data for the decoder.
+  // |on_demuxer_config_changed_cb| - Callback to inform the caller that
+  // demuxer config has changed.
   MediaDecoderJob(
       const scoped_refptr<base::SingleThreadTaskRunner>& decoder_task_runner,
-      MediaCodecBridge* media_codec_bridge,
-      const base::Closure& request_data_cb);
+      const base::Closure& request_data_cb,
+      const base::Closure& on_demuxer_config_changed_cb);
 
   // Release the output buffer at index |output_buffer_index| and render it if
   // |render_output| is true. Upon completion, |callback| will be called.
@@ -105,13 +125,32 @@ class MediaDecoderJob {
   // this decoder job.
   virtual bool ComputeTimeToRender() const = 0;
 
+  // Gets MediaCrypto object from |drm_bridge_|.
+  base::android::ScopedJavaLocalRef<jobject> GetMediaCrypto();
+
+  // Releases the |media_codec_bridge_|.
+  void ReleaseMediaCodecBridge();
+
+  MediaDrmBridge* drm_bridge() { return drm_bridge_; }
+
+  void set_is_content_encrypted(bool is_content_encrypted) {
+    is_content_encrypted_ = is_content_encrypted;
+  }
+
+  bool need_to_reconfig_decoder_job_;
+
+  scoped_ptr<MediaCodecBridge> media_codec_bridge_;
+
  private:
   friend class MediaSourcePlayerTest;
 
   // Causes this instance to be deleted on the thread it is bound to.
   void Release();
 
-  MediaCodecStatus QueueInputBuffer(const AccessUnit& unit);
+  // Queues an access unit into |media_codec_bridge_|'s input buffer. If
+  // |drain_decoder| is true,  the access unit is replaced with an EOS unit so
+  // that we can drain the current buffer in |media_codec_bridge_|.
+  MediaCodecStatus QueueInputBuffer(const AccessUnit& unit, bool drain_decoder);
 
   // Returns true if this object has data to decode.
   bool HasData() const;
@@ -135,6 +174,7 @@ class MediaDecoderJob {
                       base::TimeTicks start_time_ticks,
                       base::TimeDelta start_presentation_timestamp,
                       bool needs_flush,
+                      bool drain_decoder,
                       const DecoderCallback& callback);
 
   // Called on the UI thread to indicate that one decode cycle has completed.
@@ -147,22 +187,43 @@ class MediaDecoderJob {
   // Helper function to get the current access unit that is being decoded.
   const AccessUnit& CurrentAccessUnit() const;
 
-  // Check whether a chunk has no remaining access units to decode. If
+  // Checks whether a chunk has no remaining access units to decode. If
   // |is_active_chunk| is true, this function returns whether decoder has
   // consumed all data in |received_data_[current_demuxer_data_index_]|.
   // Otherwise, it returns whether decoder has consumed all data in the inactive
   // chunk.
   bool NoAccessUnitsRemainingInChunk(bool is_active_chunk) const;
 
-  // Clearn all the received data.
-  void ClearData();
-
-  // Request new data for the current chunk if it runs out of data.
+  // Requests new data for the current chunk if it runs out of data.
   void RequestCurrentChunkIfEmpty();
 
-  // Initialize |received_data_| and |access_unit_index_|.
+  // Initializes |received_data_| and |access_unit_index_|.
   void InitializeReceivedData();
 
+  void OnDecoderDrained();
+
+  // Creates |media_codec_bridge_| for decoding purpose.
+  bool CreateMediaCodecBridge();
+
+  // Called when an access unit is consumed by the decoder. |is_config_change|
+  // indicates whether the current access unit is a config change. If it is
+  // true, the next access unit is guarateed to be an I-frame.
+  virtual void CurrentDataConsumed(bool is_config_change) {}
+
+  // Called when |media_codec_bridge_| is released
+  virtual void OnMediaCodecBridgeReleased() {}
+
+  // Implemented by the child class to create |media_codec_bridge_| for a
+  // particular stream.
+  virtual bool CreateMediaCodecBridgeInternal() = 0;
+
+  // Returns true if the |configs| doesn't match the current demuxer configs
+  // the decoder job has.
+  virtual bool IsDemuxerConfigChanged(const DemuxerConfigs& configs) const = 0;
+
+  // Update the demuxer configs.
+  virtual void UpdateDemuxerConfigs(const DemuxerConfigs& configs) = 0;
+
   // Return the index to |received_data_| that is not currently being decoded.
   size_t inactive_demuxer_data_index() const {
     return 1 - current_demuxer_data_index_;
@@ -174,10 +235,6 @@ class MediaDecoderJob {
   // The task runner that decoder job runs on.
   scoped_refptr<base::SingleThreadTaskRunner> decoder_task_runner_;
 
-  // The media codec bridge used for decoding. Owned by derived class.
-  // NOTE: This MUST NOT be accessed in the destructor.
-  MediaCodecBridge* media_codec_bridge_;
-
   // Whether the decoder needs to be flushed.
   bool needs_flush_;
 
@@ -210,6 +267,9 @@ class MediaDecoderJob {
   // Callback used to request more data.
   base::Closure request_data_cb_;
 
+  // Callback to notify the caller config has changed.
+  base::Closure on_demuxer_config_changed_cb_;
+
   // Callback to run when new data has been received.
   base::Closure on_data_received_cb_;
 
@@ -234,6 +294,11 @@ class MediaDecoderJob {
   // If the index is uninitialized or invalid, it must be -1.
   int input_buf_index_;
 
+  // Indicates whether content is encrypted.
+  bool is_content_encrypted_;
+
+  // Indicates the decoder job should stop after decoding the current access
+  // unit.
   bool stop_decode_pending_;
 
   // Indicates that this object should be destroyed once the current
@@ -247,10 +312,17 @@ class MediaDecoderJob {
   // Indicates whether the incoming data should be ignored.
   bool is_incoming_data_invalid_;
 
-  // Weak pointer passed to media decoder jobs for callbacks. It is bounded to
-  // the decoder thread.
-  // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<MediaDecoderJob> weak_factory_;
+  // Indicates that |media_codec_bridge_| should be released once the current
+  // Decode() has completed. This gets set when ReleaseDecoderResources() gets
+  // called while there is a decode in progress.
+  bool release_resources_pending_;
+
+  // Pointer to a DRM object that will be used for encrypted streams.
+  MediaDrmBridge* drm_bridge_;
+
+  // Indicates whether |media_codec_bridge_| is in the middle of being drained
+  // due to a config change.
+  bool drain_decoder_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(MediaDecoderJob);
 };