MSE: Fix logic bugs with high precision duration

media/blink/webmediaplayer_impl.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/blink/webmediaplayer_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <limits>
 #include <string>
@@ skipping 685 matching lines @@
 
   return seeking_;
 }
 
 double WebMediaPlayerImpl::duration() const {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
   if (ready_state_ == WebMediaPlayer::ReadyStateHaveNothing)
     return std::numeric_limits<double>::quiet_NaN();
 
-  return GetPipelineDuration();
+  // Use duration from ChunkDemuxer when present. MSE allows users to specify
+  // duration as a double. This propagates to the rest of the pipeline as a
+  // TimeDelta with potentially reduced precision (limited to Microseconds).
+  // ChunkDemuxer returns the full-precision user-specified double. This ensures
+  // users can "get" the exact duration they "set".
+  if (chunk_demuxer_)
+    return chunk_demuxer_->GetDuration();
+
+  base::TimeDelta pipeline_duration = pipeline_.GetMediaDuration();
+  return pipeline_duration == kInfiniteDuration
+             ? std::numeric_limits<double>::infinity()
+             : pipeline_duration.InSecondsF();
 }
 
 double WebMediaPlayerImpl::timelineOffset() const {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
   if (pipeline_metadata_.timeline_offset.is_null())
     return std::numeric_limits<double>::quiet_NaN();
 
   return pipeline_metadata_.timeline_offset.ToJsTime();
 }
@@ skipping 942 matching lines @@
   highest_ready_state_ = std::max(highest_ready_state_, ready_state_);
 
   // Always notify to ensure client has the latest value.
   client_->readyStateChanged();
 }
 
 blink::WebAudioSourceProvider* WebMediaPlayerImpl::getAudioSourceProvider() {
   return audio_source_provider_.get();
 }
 
-double WebMediaPlayerImpl::GetPipelineDuration() const {
-  base::TimeDelta duration = pipeline_.GetMediaDuration();
-
-  // Return positive infinity if the resource is unbounded.
-  // http://www.whatwg.org/specs/web-apps/current-work/multipage/video.html#dom-media-duration
-  if (duration == kInfiniteDuration)
-    return std::numeric_limits<double>::infinity();
-
-  return duration.InSecondsF();
-}
-
 static void GetCurrentFrameAndSignal(
     VideoFrameCompositor* compositor,
     scoped_refptr<VideoFrame>* video_frame_out,
     base::WaitableEvent* event) {
   TRACE_EVENT0("media", "GetCurrentFrameAndSignal");
   *video_frame_out = compositor->GetCurrentFrameAndUpdateIfStale();
   event->Signal();
 }
 
 scoped_refptr<VideoFrame>
@@ skipping 321 matching lines @@
   return delegate_ && delegate_->IsHidden();
 }
 
 void WebMediaPlayerImpl::ActivateViewportIntersectionMonitoring(bool activate) {
   DCHECK(main_task_runner_->BelongsToCurrentThread());
 
   client_->activateViewportIntersectionMonitoring(activate);
 }
 
 }  // namespace media