add round/ceil/etc. for SkMScalar

include/core/SkFloatingPoint.h

Index: include/core/SkFloatingPoint.h
diff --git a/include/core/SkFloatingPoint.h b/include/core/SkFloatingPoint.h
index f85c456aa88cd89fc1ec9508a5826d2c01848348..1003b80b4f1109db3730c54d0b76ede4ae865703 100644
--- a/include/core/SkFloatingPoint.h
+++ b/include/core/SkFloatingPoint.h
@@ -116,6 +116,13 @@ static inline float sk_float_copysign(float x, float y) {
     #define sk_float_ceil2int(x)    (int)sk_float_ceil(x)
 #endif
 
+#define sk_double_floor(x)          floor(x)
+#define sk_double_round(x)          floor((x) + 0.5)

[Peter Kasting, 2014/10/21 18:56:09]

This doesn't match std::round() for negative numbers (this rounds toward
positive infinity instead of rounding away from 0).  Do you care?

Same issue with sk_double_round2int.

[reed1, 2014/10/21 19:08:08]

Agreed, this is very deliberate on skia's part. We want to round in a
"consistent" dirction, so that we are somewhat translation-independent.

+#define sk_double_ceil(x)           ceil(x)
+#define sk_double_floor2int(x)      (int)floor(x)
+#define sk_double_round2int(x)      (int)floor((x) + 0.5f)
+#define sk_double_ceil2int(x)       (int)ceil(x)
+
 extern const uint32_t gIEEENotANumber;
 extern const uint32_t gIEEEInfinity;
 extern const uint32_t gIEEENegativeInfinity;