Implement FlingingRenderer::GetMediaTime

This CL uses RemoteMediaPlayer.getApproximateStreamPosition to implement
FlingingRenderer::GetMediaTime().

NOTE: GMS core ignores stream position changes in the MediaStatus, when
we have a pending seek. Calling both Seek() and Play() back to back in
FlingingRenderer::StartPlayingFrom() sometimes causes the stream
position update to be lost. This causes getApproximateStreamPosition to
report a time that is out of sync with the cast device. We already use
the autoplay flag when loading the RemoteMediaPlayer, so removing the
call to MediaController::Play() doest not cause any problems.

Bug: 830871
Change-Id: Ia5a6384cf11a77a6aa49e9669f015f7835c5a775
Reviewed-on: https://chromium-review.googlesource.com/1180511Reviewed-by: Zhiqiang Zhang <zqzhang@chromium.org>
Commit-Queue: Thomas Guilbert <tguilbert@chromium.org>
Cr-Commit-Position: refs/heads/master@{#585655}

chrome/android/java/src/org/chromium/chrome/browser/media/router/FlingingControllerBridge.java

@@ -46,6 +46,11 @@ public class FlingingControllerBridge implements MediaStatusObserver {
         mFlingingController.getMediaController().seek(positionInMs);
     }
 
+    @CalledByNative
+    public long getApproximateCurrentTime() {
+        return mFlingingController.getApproximateCurrentTime();
+    }
+
     // MediaStatusObserver implementation.
     @Override
     public void onMediaStatusUpdate(MediaStatusBridge status) {

chrome/browser/media/android/remote/flinging_controller_bridge.cc

@@ -88,8 +88,13 @@ void FlingingControllerBridge::OnMediaStatusUpdated(
 }
 
 base::TimeDelta FlingingControllerBridge::GetApproximateCurrentTime() {
-  // TODO(https://crbug.com/830871): Implement this method.
-  return base::TimeDelta();
+  JNIEnv* env = base::android::AttachCurrentThread();
+  DCHECK(env);
+
+  long time_in_ms = Java_FlingingControllerBridge_getApproximateCurrentTime(
+      env, j_flinging_controller_bridge_);
+
+  return base::TimeDelta::FromMilliseconds(time_in_ms);
 }
 
 }  // namespace media_router

content/browser/media/flinging_renderer.cc

@@ -81,7 +81,6 @@ void FlingingRenderer::Flush(const base::Closure& flush_cb) {
 void FlingingRenderer::StartPlayingFrom(base::TimeDelta time) {
   DVLOG(2) << __func__;
   controller_->GetMediaController()->Seek(time);
-  controller_->GetMediaController()->Play();
 }
 
 void FlingingRenderer::SetPlaybackRate(double playback_rate) {
@@ -98,8 +97,7 @@ void FlingingRenderer::SetVolume(float volume) {
 }
 
 base::TimeDelta FlingingRenderer::GetMediaTime() {
-  // TODO(https://crbug.com/830871): return correct media time.
-  return base::TimeDelta();
+  return controller_->GetApproximateCurrentTime();
 }
 
 void FlingingRenderer::OnMediaStatusUpdated(const media::MediaStatus& status) {

content/browser/media/flinging_renderer_unittest.cc

@@ -61,14 +61,12 @@ class FlingingRendererTest : public testing::Test {
 
 TEST_F(FlingingRendererTest, StartPlayingFromTime) {
   base::TimeDelta seek_time = base::TimeDelta::FromSeconds(10);
-  EXPECT_CALL(*media_controller_, Play());
   EXPECT_CALL(*media_controller_, Seek(seek_time));
 
   renderer_->StartPlayingFrom(seek_time);
 }
 
 TEST_F(FlingingRendererTest, StartPlayingFromBeginning) {
-  EXPECT_CALL(*media_controller_, Play());
   EXPECT_CALL(*media_controller_, Seek(base::TimeDelta()));
 
   renderer_->StartPlayingFrom(base::TimeDelta());