Revert of Use webrtc::VideoFrame timestamp in RTCVideoEncoder (patchset

#7 id:260001 of https://codereview.chromium.org/2205623002/ )

Reason for revert:
This CL caused some regressions regarding BWE stats and HW encoder
performance. Reasons include:
1) Modifying scoped_refptr<media::VideoFrame>'s timestamp causes problems
for other clients using the same media::VideoFrame.
2) WebRTC's RTP timestamp isn't suitable for using as presentation timestamp
in Mac and Win HW encoders.

BUG=641230

Original issue's description:
> Use webrtc::VideoFrame timestamp in RTCVideoEncoder
>
> This CL fixes input timestamp mismatch in RTCVideoEncoder, which
> broke googAvgEncodeMs and googEncodeUsagePercent stats in webrtc-internals
> for hardware encoders.
> With this change, we start using WebRTC given timestamp() so that
> OveruseFrameDetector can match the timestamps and calculate the stats.
>
> BUG=597087
> TEST=googAvgEncodeMs and googEncodeUsagePercent works on Mac(H264) and
> veyron_jerry(VP8).
>
> Committed: https://crrev.com/e3195490a63d9545fb1bfe560aa21680ba0b5843
> Cr-Commit-Position: refs/heads/master@{#414589}

TBR=wuchengli@chromium.org,pbos@chromium.org,posciak@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=597087

Review-Url: https://codereview.chromium.org/2296273002
Cr-Commit-Position: refs/heads/master@{#415752}

content/renderer/media/gpu/rtc_video_encoder.cc

@@ -32,9 +32,6 @@ namespace content {
 
 namespace {
 
-// Used for timestamp conversions.
-static const int64_t kMsToRtpTimestamp = 90;
-
 // Translate from webrtc::VideoCodecType and webrtc::VideoCodec to
 // media::VideoCodecProfile.
 media::VideoCodecProfile WebRTCVideoCodecToVideoCodecProfile(
@@ -477,25 +474,27 @@ void RTCVideoEncoder::Impl::BitstreamBufferReady(int32_t bitstream_buffer_id,
   output_buffers_free_count_--;
 
   // Derive the capture time (in ms) and RTP timestamp (in 90KHz ticks).
-  int64_t rtp_timestamp, capture_time_ms;
+  int64_t capture_time_us, capture_time_ms;
+  uint32_t rtp_timestamp;
+
   if (!timestamp.is_zero()) {
-    // Get RTP timestamp value.
-    rtp_timestamp = timestamp.ToInternalValue();
-    capture_time_ms = rtp_timestamp / kMsToRtpTimestamp;
+    capture_time_us = timestamp.InMicroseconds();;
+    capture_time_ms = timestamp.InMilliseconds();
   } else {
     // Fallback to the current time if encoder does not provide timestamp.
-    rtp_timestamp = rtc::TimeMicros() * kMsToRtpTimestamp /
-                    base::Time::kMicrosecondsPerMillisecond;
-    capture_time_ms =
-        rtc::TimeMicros() / base::Time::kMicrosecondsPerMillisecond;
+    capture_time_us = rtc::TimeMicros();
+    capture_time_ms = capture_time_us / base::Time::kMicrosecondsPerMillisecond;
   }
+  // RTP timestamp can wrap around. Get the lower 32 bits.
+  rtp_timestamp = static_cast<uint32_t>(
+      capture_time_us * 90 / base::Time::kMicrosecondsPerMillisecond);
 
   webrtc::EncodedImage image(
       reinterpret_cast<uint8_t*>(output_buffer->memory()), payload_size,
       output_buffer->mapped_size());
   image._encodedWidth = input_visible_size_.width();
   image._encodedHeight = input_visible_size_.height();
-  image._timeStamp = static_cast<uint32_t>(rtp_timestamp);
+  image._timeStamp = rtp_timestamp;
   image.capture_time_ms_ = capture_time_ms;
   image._frameType =
       (key_frame ? webrtc::kVideoFrameKey : webrtc::kVideoFrameDelta);
@@ -572,13 +571,15 @@ void RTCVideoEncoder::Impl::EncodeOneFrame() {
   }
 
   if (requires_copy) {
+    const base::TimeDelta timestamp =
+        frame ? frame->timestamp()
+              : base::TimeDelta::FromMilliseconds(next_frame->ntp_time_ms());
     base::SharedMemory* input_buffer = input_buffers_[index];
     frame = media::VideoFrame::WrapExternalSharedMemory(
         media::PIXEL_FORMAT_I420, input_frame_coded_size_,
         gfx::Rect(input_visible_size_), input_visible_size_,
         reinterpret_cast<uint8_t*>(input_buffer->memory()),
-        input_buffer->mapped_size(), input_buffer->handle(), 0,
-        base::TimeDelta());
+        input_buffer->mapped_size(), input_buffer->handle(), 0, timestamp);
     if (!frame.get()) {
       LogAndNotifyError(FROM_HERE, "failed to create frame",
                         media::VideoEncodeAccelerator::kPlatformFailureError);
@@ -610,9 +611,6 @@ void RTCVideoEncoder::Impl::EncodeOneFrame() {
       return;
     }
   }
-  // Use the timestamp set from WebRTC and set it in 90 kHz.
-  frame->set_timestamp(
-      base::TimeDelta::FromInternalValue(next_frame->timestamp()));
   frame->AddDestructionObserver(media::BindToCurrentLoop(
       base::Bind(&RTCVideoEncoder::Impl::EncodeFrameFinished, this, index)));
   video_encoder_->Encode(frame, next_frame_keyframe);

media/gpu/video_encode_accelerator_unittest.cc

@@ -570,9 +570,6 @@ class H264Validator : public StreamValidator {
 void H264Validator::ProcessStreamBuffer(const uint8_t* stream, size_t size) {
   h264_parser_.SetStream(stream, static_cast<off_t>(size));
 
-  // Run |frame_cb_| for only first nalu.
-  bool frame_cb_called = false;
-
   while (1) {
     H264NALU nalu;
     H264Parser::Result result;
@@ -593,14 +590,10 @@ void H264Validator::ProcessStreamBuffer(const uint8_t* stream, size_t size) {
         keyframe = true;
       // fallthrough
       case H264NALU::kNonIDRSlice: {
-        // Stream may contain at most one frame.
         ASSERT_TRUE(seen_idr_);
         seen_sps_ = seen_pps_ = false;
-        if (!frame_cb_called) {
-          frame_cb_called = true;
-          if (!frame_cb_.Run(keyframe))
-            return;
-        }
+        if (!frame_cb_.Run(keyframe))
+          return;
         break;
       }
 
@@ -1850,15 +1843,6 @@ INSTANTIATE_TEST_CASE_P(MultipleEncoders,
                                                           false,
                                                           false,
                                                           false)));
-
-#if defined(OS_MACOSX)
-INSTANTIATE_TEST_CASE_P(
-    VerifyTimestamp,
-    VideoEncodeAcceleratorTest,
-    ::testing::Values(
-        std::make_tuple(1, false, 0, false, false, false, false, false, true)));
-#endif  // defined(OS_MACOSX)
-
 #if defined(OS_WIN)
 INSTANTIATE_TEST_CASE_P(
     ForceBitrate,