Cast: Avoid hitting a DCHECK caused by race condition

RTCP sender report has a race condition when then current time is
submitted asynchronously (from another process). This caused the value
for DLRR to be negative.

This code is going to be removed it is fine to just suppress this
condition.

BUG=393042
NOTRY=true

Review URL: https://codereview.chromium.org/410433002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@284521 0039d316-1c4b-4281-b951-d872f2087c98

media/cast/net/rtcp/rtcp.cc

@@ -159,14 +159,6 @@ void Rtcp::SendRtcpFromRtpReceiver(
       uint32 delay_seconds = 0;
       uint32 delay_fraction = 0;
       base::TimeDelta delta = now - time_last_report_received_;
-
-      // TODO(hclam): DLRR is not used by any receiver. Consider removing
-      // it. There is one race condition in the computation of the time for
-      // DLRR: current time is submitted to this method while
-      // |time_last_report_received_| is updated just before that. This can
-      // happen if current time is not submitted synchronously.
-      if (delta < base::TimeDelta())
-        delta = base::TimeDelta();
       ConvertTimeToFractions(delta.InMicroseconds(), &delay_seconds,
                              &delay_fraction);
       report_block.delay_since_last_sr =
@@ -202,6 +194,13 @@ void Rtcp::SendRtcpFromRtpSender(base::TimeTicks current_time,
     uint32 delay_seconds = 0;
     uint32 delay_fraction = 0;
     base::TimeDelta delta = current_time - time_last_report_received_;
+    // TODO(hclam): DLRR is not used by any receiver. Consider removing
+    // it. There is one race condition in the computation of the time for
+    // DLRR: current time is submitted to this method while
+    // |time_last_report_received_| is updated just before that. This can
+    // happen if current time is not submitted synchronously.
+    if (delta < base::TimeDelta())
+      delta = base::TimeDelta();
     ConvertTimeToFractions(delta.InMicroseconds(), &delay_seconds,
                            &delay_fraction);