[Cast] Repair receiver playout time calculations and frame skip logic.

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 b0f9370186e9e60e2cd0a7dc0f8032d603ea4e4a..94f0ef82f10d78199ae49d87c1e95d22db5099eb 100644
--- a/media/cast/cast_defines.h
+++ b/media/cast/cast_defines.h
@@ -7,6 +7,7 @@
 
 #include <stdint.h>
 
+#include <limits>
 #include <map>
 #include <set>
 
@@ -135,13 +136,17 @@ inline base::TimeDelta ConvertFromNtpDiff(uint32 ntp_delay) {
   return base::TimeDelta::FromMilliseconds(delay_ms);
 }
 
-inline void ConvertTimeToFractions(int64 time_us,
+inline void ConvertTimeToFractions(int64 ntp_time_us,
                                    uint32* seconds,
                                    uint32* fractions) {
-  DCHECK_GE(time_us, 0) << "Time must NOT be negative";
-  *seconds = static_cast<uint32>(time_us / base::Time::kMicrosecondsPerSecond);
+  DCHECK_GE(ntp_time_us, 0) << "Time must NOT be negative";
+  const int64 seconds_component =
+      ntp_time_us / base::Time::kMicrosecondsPerSecond;
+  CHECK(seconds_component <= std::numeric_limits<uint32>::max());

[hubbe, 2014/05/14 23:12:23]

When will this wrap?
What happens when if wraps?

[miu, 2014/05/16 22:45:47]

Done.  Documented.

+  *seconds = static_cast<uint32>(seconds_component);
   *fractions = static_cast<uint32>(
-      (time_us % base::Time::kMicrosecondsPerSecond) * kMagicFractionalUnit);
+      (ntp_time_us % base::Time::kMicrosecondsPerSecond) *
+          kMagicFractionalUnit);
 }
 
 inline void ConvertTimeTicksToNtp(const base::TimeTicks& time,