Remove include of stdlib.h from SkTypes.h.

src/core/SkTime.cpp

Index: src/core/SkTime.cpp
diff --git a/src/core/SkTime.cpp b/src/core/SkTime.cpp
index b8e42365ef930be154a219d2cd74701a709373f5..fa6c04447de0ade9f8bfaf927151215d6eec85ec 100644
--- a/src/core/SkTime.cpp
+++ b/src/core/SkTime.cpp
@@ -12,8 +12,8 @@ void SkTime::DateTime::toISO8601(SkString* dst) const {
     if (dst) {
         int timeZoneMinutes = SkToInt(fTimeZoneMinutes);
         char timezoneSign = timeZoneMinutes >= 0 ? '+' : '-';
-        int timeZoneHours = abs(timeZoneMinutes) / 60;
-        timeZoneMinutes = abs(timeZoneMinutes) % 60;
+        int timeZoneHours = SkTAbs(timeZoneMinutes) / 60;
+        timeZoneMinutes = SkTAbs(timeZoneMinutes) % 60;
         dst->printf("%04u-%02u-%02uT%02u:%02u:%02u%c%02d:%02d",
                     static_cast<unsigned>(fYear), static_cast<unsigned>(fMonth),
                     static_cast<unsigned>(fDay), static_cast<unsigned>(fHour),