Change to calculate the real NTP in TimeTicks.

media/cast/cast_defines.h

Index: media/cast/cast_defines.h
diff --git a/media/cast/cast_defines.h b/media/cast/cast_defines.h
index 0778638551eec7f9559bb5e6190549c396a90baf..ac0f2166556f3dbc1509546a2b96ddbaede05f99 100644
--- a/media/cast/cast_defines.h
+++ b/media/cast/cast_defines.h
@@ -58,12 +58,6 @@ typedef std::map<uint8, PacketIdSet> MissingFramesAndPacketsMap;
 // fractional NTP seconds.
 static const double kMagicFractionalUnit = 4.294967296E3;
 
-// Network Time Protocol (NTP), which is in seconds relative to 0h UTC on
-// 1 January 1900.
-static const int64 kNtpEpochDeltaSeconds = GG_INT64_C(9435484800);
-static const int64 kNtpEpochDeltaMicroseconds =
-    kNtpEpochDeltaSeconds * base::Time::kMicrosecondsPerSecond;
-
 inline bool IsNewerFrameId(uint8 frame_id, uint8 prev_frame_id) {
   return (frame_id != prev_frame_id) &&
       static_cast<uint8>(frame_id - prev_frame_id) < 0x80;
@@ -110,7 +104,7 @@ inline void ConvertTimeToFractions(int64 time_us,
 inline void ConvertTimeToNtp(const base::TimeTicks& time,
                              uint32* ntp_seconds,
                              uint32* ntp_fractions) {
-  int64 time_us = time.ToInternalValue() - kNtpEpochDeltaMicroseconds;
+  int64 time_us = time.ToInternalValue();

[miu, 2013/10/23 18:24:02]

IMHO, it's much cleaner to work with only one timeline in the cast code. 
Meaning, I'd suggest you only convert to/from NTP time for the packets, but
otherwise have all other code be on the same timeline (i.e., same origin) as
base::TimeTicks::Now().

[pwestin, 2013/10/23 21:07:49]

Removed this function since it did not provide any value any longer

   ConvertTimeToFractions(time_us, ntp_seconds, ntp_fractions);
 }
 
@@ -119,8 +113,7 @@ inline base::TimeTicks ConvertNtpToTime(uint32 ntp_seconds,
   int64 ntp_time_us = static_cast<int64>(ntp_seconds) *
        base::Time::kMicrosecondsPerSecond;
   ntp_time_us += static_cast<int64>(ntp_fractions) / kMagicFractionalUnit;
-  return base::TimeTicks::FromInternalValue(ntp_time_us +
-      kNtpEpochDeltaMicroseconds);
+  return base::TimeTicks::FromInternalValue(ntp_time_us);
 }
 
 }  // namespace cast