Drop idle MediaCodec instances after a few seconds within AVDA.

media/gpu/android_video_decode_accelerator.cc

Index: media/gpu/android_video_decode_accelerator.cc
diff --git a/media/gpu/android_video_decode_accelerator.cc b/media/gpu/android_video_decode_accelerator.cc
index 5b8c856701c5645cd6324720a9d1086ba9b0532c..0a3e80833caa228133350c22fc65b464601144a3 100644
--- a/media/gpu/android_video_decode_accelerator.cc
+++ b/media/gpu/android_video_decode_accelerator.cc
@@ -109,6 +109,12 @@ static inline const base::TimeDelta ErrorPostingDelay() {
   return base::TimeDelta::FromSeconds(2);
 }
 
+// Time allowed to elapse between codec configuration completion and the first
+// Decode() callback. Unless a site is intentionally stalling after providing
+// initialization information, this timeout should never be hit.
+constexpr base::TimeDelta kNoDecodeIdleTimeout =
+    base::TimeDelta::FromSeconds(1);
+
 // For RecordFormatChangedMetric.
 enum FormatChangedValue {
   CodecInitialized = false,
@@ -963,6 +969,7 @@ void AndroidVideoDecodeAccelerator::SendDecodedFrameToClient(
 void AndroidVideoDecodeAccelerator::Decode(
     const BitstreamBuffer& bitstream_buffer) {
   DCHECK(thread_checker_.CalledOnValidThread());
+  no_decode_timeout_.Stop();
 
   // If we previously deferred a codec restart, take care of it now. This can
   // happen on older devices where configuration changes require a codec reset.
@@ -1202,7 +1209,8 @@ void AndroidVideoDecodeAccelerator::OnCodecConfigured(
   }
 
   state_ = NO_ERROR;
-
+  no_decode_timeout_.Start(FROM_HERE, kNoDecodeIdleTimeout, this,
+                           &AndroidVideoDecodeAccelerator::CloseIdleCodec);
   ManageTimer(true);
 }
 
@@ -1311,7 +1319,7 @@ void AndroidVideoDecodeAccelerator::ResetCodecState() {
   // Prior to JB-MR2, flush() had several bugs (b/8125974, b/8347958) so we must
   // delete the MediaCodec and create a new one. The full reconfigure is much
   // slower and may cause visible freezing if done mid-stream.
-  if (!did_codec_error_happen &&
+  if (!did_codec_error_happen && media_codec_ &&
       base::android::BuildInfo::GetInstance()->sdk_int() >= 18) {
     DVLOG(3) << __FUNCTION__ << " Flushing MediaCodec.";
     media_codec_->Flush();
@@ -1671,6 +1679,8 @@ void AndroidVideoDecodeAccelerator::ReleaseMediaCodec() {
   if (!media_codec_)
     return;
 
+  no_decode_timeout_.Stop();
+
   // If codec construction is broken, then we can't release this codec if it's
   // backed by hardware, else it may hang too.  Post it to the construction
   // thread, and it'll get freed if things start working.  If things are
@@ -1786,4 +1796,12 @@ bool AndroidVideoDecodeAccelerator::IsMediaCodecSoftwareDecodingForbidden()
                                    codec_config_->codec_ == media::kCodecVP9);
 }
 
+void AndroidVideoDecodeAccelerator::CloseIdleCodec() {
+  if (!media_codec_)
+    return;
+
+  ReleaseMediaCodec();
+  codec_needs_reset_ = true;

[watk, 2016/07/13 22:38:25]

Do we need to call strategy_->CodecChanged(nullptr)?

I feel like the answer is no, but just wanted to double check you'd thought
about it.

[liberato (no reviews please), 2016/07/14 15:33:57]

i don't think that we do, since no decode has been issued => no frames
outstanding.  however, it's probably a good idea since it's safe to call
CodecChanged here, and more robust.

good catch.

+}
+
 }  // namespace media