Interpolate media time for mojo rendering pipeline.

media/mojo/clients/mojo_renderer_unittest.cc

Index: media/mojo/clients/mojo_renderer_unittest.cc
diff --git a/media/mojo/clients/mojo_renderer_unittest.cc b/media/mojo/clients/mojo_renderer_unittest.cc
index 173db36668bc42e97bf16aec155e55443926e31b..e52808e45d4c7c608b09b80a0177462941449756 100644
--- a/media/mojo/clients/mojo_renderer_unittest.cc
+++ b/media/mojo/clients/mojo_renderer_unittest.cc
@@ -9,6 +9,7 @@
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/threading/platform_thread.h"
+#include "base/timer/elapsed_timer.h"
 #include "media/base/audio_renderer_sink.h"
 #include "media/base/cdm_config.h"
 #include "media/base/cdm_context.h"
@@ -36,6 +37,7 @@ using ::testing::StrictMock;
 
 namespace media {
 
+namespace {
 const int64_t kStartPlayingTimeInMs = 100;
 const char kClearKeyKeySystem[] = "org.w3.clearkey";
 
@@ -43,6 +45,14 @@ ACTION_P2(SetError, renderer_client, error) {
   renderer_client->OnError(error);
 }
 
+void WaitFor(base::TimeDelta duration) {

[DaleCurtis, 2016/09/06 19:21:25]

Does RunLoop().RunUntilIdle() not suffice?

[alokp, 2016/09/07 16:46:21]

I want a few of the time-update tasks to be posted, which happen on a timer:
https://cs.chromium.org/chromium/src/media/mojo/services/mojo_renderer_servic...

+  base::RunLoop run_loop;
+  base::ThreadTaskRunnerHandle::Get()->PostDelayedTask(
+      FROM_HERE, run_loop.QuitClosure(), duration);
+  run_loop.Run();
+}
+}  // namespace
+
 class MojoRendererTest : public ::testing::Test {
  public:
   MojoRendererTest() {
@@ -235,6 +245,7 @@ TEST_F(MojoRendererTest, Initialize_AfterConnectionError) {
 
 TEST_F(MojoRendererTest, Flush_Success) {
   Initialize();
+  Play();

[alokp, 2016/09/02 22:51:18]

It is illegal to call Flush when Renderer is not playing. I ran into
TimeDeltaInterpolator DCHECK here:
https://cs.chromium.org/chromium/src/media/base/time_delta_interpolator.cc?dr...

Because I unconditionally call TimeDeltaInterpolator::StopInterpolating on Flush
because I assume that it must have been started on StartPlayingFrom. This is
consistent with:
https://cs.chromium.org/chromium/src/media/renderers/renderer_impl.cc?dr=CSs&...

[DaleCurtis, 2016/09/06 19:21:25]

Add DCHECK in Mojo renderer?

[alokp, 2016/09/07 16:46:21]

I was wrong about Flush being illegal. RendererImpl gets into STATE_PLAYING
after a successful initialization. StartPlayingFrom does not need to get called:
https://cs.chromium.org/chromium/src/media/renderers/renderer_impl.cc?dr=CSs&...

We already have a DCHECK in MojoRendererService:
https://cs.chromium.org/chromium/src/media/mojo/services/mojo_renderer_servic...

In the new patch I avoid calling StopInterpolating if the interpolator is not
interpolating to avoid the DCHECK. But I wonder if StopInterpolating should even
DCHECK. IMO it should be a no-op if it is not interpolating.

 
   EXPECT_CALL(*mock_renderer_, Flush(_)).WillOnce(RunClosure<0>());
   Flush();
@@ -242,6 +253,7 @@ TEST_F(MojoRendererTest, Flush_Success) {
 
 TEST_F(MojoRendererTest, Flush_ConnectionError) {
   Initialize();
+  Play();

[alokp, 2016/09/02 22:51:17]

ditto.

 
   // Upon connection error, OnError() should be called once and only once.
   EXPECT_CALL(renderer_client_, OnError(PIPELINE_ERROR_DECODE)).Times(1);
@@ -326,15 +338,37 @@ TEST_F(MojoRendererTest, GetMediaTime) {
   Initialize();
   EXPECT_EQ(base::TimeDelta(), mojo_renderer_->GetMediaTime());
 
-  Play();
+  const base::TimeDelta kSleepTime = base::TimeDelta::FromMilliseconds(500);
+  const base::TimeDelta kStartTime =
+      base::TimeDelta::FromMilliseconds(kStartPlayingTimeInMs);
 
-  // Time is updated periodically with a short delay.
-  const base::TimeDelta kUpdatedTime = base::TimeDelta::FromMilliseconds(500);
+  // Media time should not advance since playback rate is 0.
+  EXPECT_CALL(*mock_renderer_, SetPlaybackRate(0));
+  EXPECT_CALL(*mock_renderer_, StartPlayingFrom(kStartTime));
   EXPECT_CALL(*mock_renderer_, GetMediaTime())
-      .WillRepeatedly(Return(kUpdatedTime));
-  base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(100));
-  base::RunLoop().RunUntilIdle();
-  EXPECT_EQ(kUpdatedTime, mojo_renderer_->GetMediaTime());
+      .WillRepeatedly(Return(kStartTime));
+  mojo_renderer_->SetPlaybackRate(0);
+  mojo_renderer_->StartPlayingFrom(kStartTime);
+  WaitFor(kSleepTime);
+  EXPECT_EQ(kStartTime, mojo_renderer_->GetMediaTime());
+
+  // Media time should now advance since playback rate is > 0.
+  std::unique_ptr<base::ElapsedTimer> elapsed_timer(new base::ElapsedTimer);
+  EXPECT_CALL(*mock_renderer_, SetPlaybackRate(1.0));
+  EXPECT_CALL(*mock_renderer_, GetMediaTime())
+      .WillRepeatedly(Return(elapsed_timer->Elapsed()));
+  mojo_renderer_->SetPlaybackRate(1.0);
+  WaitFor(kSleepTime);
+  EXPECT_GT(mojo_renderer_->GetMediaTime(), kStartTime);
+
+  // Flushing should pause media-time updates.
+  EXPECT_CALL(*mock_renderer_, Flush(_)).WillOnce(RunClosure<0>());
+  Flush();
+  base::TimeDelta pause_time = mojo_renderer_->GetMediaTime();
+  EXPECT_GT(pause_time, kStartTime);
+  WaitFor(kSleepTime);
+  EXPECT_EQ(pause_time, mojo_renderer_->GetMediaTime());
+  Destroy();
 }
 
 TEST_F(MojoRendererTest, OnEnded) {
@@ -371,6 +405,8 @@ TEST_F(MojoRendererTest, Destroy_PendingFlush) {
 
 TEST_F(MojoRendererTest, Destroy_PendingSetCdm) {
   Initialize();
+  Play();

[alokp, 2016/09/02 22:51:17]

ditto

+
   EXPECT_CALL(*mock_renderer_, Flush(_)).WillRepeatedly(RunClosure<0>());
   EXPECT_CALL(*this, OnFlushed());
   mojo_renderer_->Flush(