third_party/protobuf: Update to HEAD (f52e188fe4)

third_party/protobuf/src/google/protobuf/util/time_util.cc

Index: third_party/protobuf/src/google/protobuf/util/time_util.cc
diff --git a/third_party/protobuf/src/google/protobuf/util/time_util.cc b/third_party/protobuf/src/google/protobuf/util/time_util.cc
index c782d691a874bbf075fabba91d431cc84e925ff4..b11f822ad9cecfe655eebfb4fe141feace685a6b 100644
--- a/third_party/protobuf/src/google/protobuf/util/time_util.cc
+++ b/third_party/protobuf/src/google/protobuf/util/time_util.cc
@@ -142,6 +142,15 @@ int64 RoundTowardZero(int64 value, int64 divider) {
 }
 }  // namespace
 
+// Actually define these static const integers. Required by C++ standard (but
+// some compilers don't like it).
+#ifndef _MSC_VER
+const int64 TimeUtil::kTimestampMinSeconds;
+const int64 TimeUtil::kTimestampMaxSeconds;
+const int64 TimeUtil::kDurationMaxSeconds;
+const int64 TimeUtil::kDurationMinSeconds;
+#endif  // !_MSC_VER
+
 string TimeUtil::ToString(const Timestamp& timestamp) {
   return FormatTime(timestamp.seconds(), timestamp.nanos());
 }
@@ -174,7 +183,7 @@ string TimeUtil::ToString(const Duration& duration) {
     seconds = -seconds;
     nanos = -nanos;
   }
-  result += StringPrintf("%" GOOGLE_LL_FORMAT "d", seconds);
+  result += SimpleItoa(seconds);
   if (nanos != 0) {
     result += "." + FormatNanos(nanos);
   }