Initialize media timeline correctly for positive start times.

media/filters/ffmpeg_demuxer_unittest.cc

Index: media/filters/ffmpeg_demuxer_unittest.cc
diff --git a/media/filters/ffmpeg_demuxer_unittest.cc b/media/filters/ffmpeg_demuxer_unittest.cc
index d20d1aaa5a5dcf773e697c3431282dd0b2f00363..36e4824b82a538322c343182384604502751dee2 100644
--- a/media/filters/ffmpeg_demuxer_unittest.cc
+++ b/media/filters/ffmpeg_demuxer_unittest.cc
@@ -447,9 +447,8 @@ TEST_F(FFmpegDemuxerTest, Read_VideoPositiveStartTime) {
     // audio).
     EXPECT_EQ(audio_start_time, demuxer_->start_time());
 
-    // Verify that the timeline offset has been adjusted by the start time.
-    EXPECT_EQ(kTimelineOffsetMs + audio_start_time.InMilliseconds(),
-              demuxer_->GetTimelineOffset().ToJavaTime());
+    // Verify that the timeline offset has not been adjusted by the start time.
+    EXPECT_EQ(kTimelineOffsetMs, demuxer_->GetTimelineOffset().ToJavaTime());
 
     // Seek back to the beginning and repeat the test.
     WaitableMessageLoopEvent event;
@@ -549,6 +548,10 @@ TEST_F(FFmpegDemuxerTest, Read_AudioNegativeStartTimeAndOggDiscard_Sync) {
     EXPECT_EQ(base::TimeDelta::FromMicroseconds(-2902),
               demuxer_->start_time());
 
+    // Though the internal start time may be below zero, the exposed media time
+    // must always be greater than zero.
+    EXPECT_EQ(base::TimeDelta(), demuxer_->GetStartTime());
+
     video->Read(NewReadCB(FROM_HERE, 9997, 0));
     message_loop_.Run();