Remove include of stdlib.h from SkTypes.h.

src/core/SkTime.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkString.h"
 #include "SkTime.h"
 
 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),
                     static_cast<unsigned>(fMinute),
                     static_cast<unsigned>(fSecond), timezoneSign, timeZoneHours,
                     timeZoneMinutes);
     }
 }