Fix UMA metrics for MediaSourcePlayer.

media/base/android/media_statistics.cc

Index: media/base/android/media_statistics.cc
diff --git a/media/base/android/media_statistics.cc b/media/base/android/media_statistics.cc
index 19c0298e6ce0e7aa0ddac068410dca684edb8812..e1a97bc03c4cbf7b381e803e82e0a644fc3bd7ca 100644
--- a/media/base/android/media_statistics.cc
+++ b/media/base/android/media_statistics.cc
@@ -50,8 +50,8 @@ void MediaStatistics::Start(base::TimeDelta current_playback_time) {
 void MediaStatistics::StopAndReport(base::TimeDelta current_playback_time) {
   DVLOG(1) << __FUNCTION__;
 
-  if (start_time_ == kNoTimestamp())
-    return;  // skip if there was no prior Start().
+  if (start_time_ == kNoTimestamp() || current_playback_time == kNoTimestamp())
+    return;  // skip if there was no prior Start() or current time is wrong.
 
   base::TimeDelta duration = current_playback_time - start_time_;