ReleaseOutputBuffer to surface back and front buffers where possible.

content/common/gpu/media/android_video_decode_accelerator.cc

Index: content/common/gpu/media/android_video_decode_accelerator.cc
diff --git a/content/common/gpu/media/android_video_decode_accelerator.cc b/content/common/gpu/media/android_video_decode_accelerator.cc
index 0f23cefc87289e7e34c7f238a9af54433d37ca9f..ff35431dd4d3fc993ce7d38e891ac36e343f39d8 100644
--- a/content/common/gpu/media/android_video_decode_accelerator.cc
+++ b/content/common/gpu/media/android_video_decode_accelerator.cc
@@ -502,13 +502,14 @@ void AndroidVideoDecodeAccelerator::SetCdm(int cdm_id) {
 void AndroidVideoDecodeAccelerator::DoIOTask(bool start_timer) {
   DCHECK(thread_checker_.CalledOnValidThread());
   TRACE_EVENT0("media", "AVDA::DoIOTask");
-  if (state_ == ERROR || state_ == WAITING_FOR_CODEC) {
+  if (state_ == ERROR || state_ == WAITING_FOR_CODEC)
     return;
-  }
 
+  strategy_->MaybeRenderEarly(pictures_out_for_display_);
   bool did_work = QueueInput();
   while (DequeueOutput())
     did_work = true;
+  strategy_->MaybeRenderEarly(pictures_out_for_display_);

[liberato (no reviews please), 2016/04/22 00:51:05]

i see why you'd want to call this periodically, but why twice?

[DaleCurtis, 2016/04/22 01:33:58]

I was thinking that there may be work after DequeueOutput() but after
consideration that case is already covered by SendDecodedFrameToClient().

 
   ManageTimer(did_work || start_timer);
 }
@@ -819,6 +820,8 @@ void AndroidVideoDecodeAccelerator::SendDecodedFrameToClient(
     return;
   }
 
+  pictures_out_for_display_.push_back(picture_buffer_id);
+
   bool size_changed = false;
   if (i->second.size() != size_) {
     // Size may have changed due to resolution change since the last time this
@@ -829,7 +832,8 @@ void AndroidVideoDecodeAccelerator::SendDecodedFrameToClient(
 
   // Connect the PictureBuffer to the decoded frame, via whatever
   // mechanism the strategy likes.
-  strategy_->UseCodecBufferForPictureBuffer(codec_buffer_index, i->second);
+  strategy_->UseCodecBufferForPictureBuffer(codec_buffer_index, i->second,
+                                            pictures_out_for_display_);
 
   const bool allow_overlay = strategy_->ArePicturesOverlayable();
 
@@ -918,6 +922,10 @@ void AndroidVideoDecodeAccelerator::ReusePictureBuffer(
   DCHECK(thread_checker_.CalledOnValidThread());
 
   free_picture_ids_.push(picture_buffer_id);
+  pictures_out_for_display_.erase(
+      std::remove(pictures_out_for_display_.begin(),
+                  pictures_out_for_display_.end(), picture_buffer_id),
+      pictures_out_for_display_.end());
   TRACE_COUNTER1("media", "AVDA::FreePictureIds", free_picture_ids_.size());
 
   OutputBufferMap::const_iterator i =
@@ -928,7 +936,7 @@ void AndroidVideoDecodeAccelerator::ReusePictureBuffer(
     return;
   }
 
-  strategy_->ReuseOnePictureBuffer(i->second);
+  strategy_->ReuseOnePictureBuffer(i->second, pictures_out_for_display_);
   DoIOTask(true);
 }