Remove include of stdlib.h from SkTypes.h.

src/pathops/SkPathOpsTypes.cpp

Index: src/pathops/SkPathOpsTypes.cpp
diff --git a/src/pathops/SkPathOpsTypes.cpp b/src/pathops/SkPathOpsTypes.cpp
index c3de93a94a58386ba66af79e7ed8f90fdcdd7aee..bf43c1465942fe985de9230905872977b023918e 100644
--- a/src/pathops/SkPathOpsTypes.cpp
+++ b/src/pathops/SkPathOpsTypes.cpp
@@ -160,7 +160,7 @@ int UlpsDistance(float a, float b) {
         return a == b ? 0 : SK_MaxS32;
     }
     // Find the difference in ULPs.
-    return abs(floatIntA.fSignBitInt - floatIntB.fSignBitInt);
+    return SkTAbs(floatIntA.fSignBitInt - floatIntB.fSignBitInt);
 }
 
 // cube root approximation using bit hack for 64-bit float