Fix unit test failures with estimated durations and splice frames.

media/formats/webm/webm_cluster_parser.cc

Index: media/formats/webm/webm_cluster_parser.cc
diff --git a/media/formats/webm/webm_cluster_parser.cc b/media/formats/webm/webm_cluster_parser.cc
index 5530815caa8a13dffb70578942314fd3a58a5637..5a3adc363d30ba7309a0e82cd49d00c6e7d2a4cb 100644
--- a/media/formats/webm/webm_cluster_parser.cc
+++ b/media/formats/webm/webm_cluster_parser.cc
@@ -532,8 +532,18 @@ bool WebMClusterParser::Track::QueueBuffer(
     return false;
   }
 
-  estimated_next_frame_duration_ = std::max(duration,
-                                            estimated_next_frame_duration_);
+  // The estimated frame duration is the minimum non-zero duration since the
+  // last initialization segment.  The minimum is used to ensure frame durations
+  // aren't overestimated.
+  if (duration > base::TimeDelta()) {
+    if (estimated_next_frame_duration_ == kNoTimestamp()) {
+      estimated_next_frame_duration_ = duration;
+    } else {
+      estimated_next_frame_duration_ =
+          std::min(duration, estimated_next_frame_duration_);
+    }
+  }
+
   buffers_.push_back(buffer);
   return true;
 }