Add SkScalarTruncToScalar and speed up SkScalarFraction.

include/private/SkFloatingPoint.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkFloatingPoint_DEFINED
@@ skipping 17 matching lines @@
 static inline float sk_float_pow(float base, float exp) {
     return powf(base, exp);
 }
 
 #define sk_float_sqrt(x)        sqrtf(x)
 #define sk_float_sin(x)         sinf(x)
 #define sk_float_cos(x)         cosf(x)
 #define sk_float_tan(x)         tanf(x)
 #define sk_float_floor(x)       floorf(x)
 #define sk_float_ceil(x)        ceilf(x)
+#define sk_float_trunc(x)       truncf(x)
 #ifdef SK_BUILD_FOR_MAC
 #    define sk_float_acos(x)    static_cast<float>(acos(x))
 #    define sk_float_asin(x)    static_cast<float>(asin(x))
 #else
 #    define sk_float_acos(x)    acosf(x)
 #    define sk_float_asin(x)    asinf(x)
 #endif
 #define sk_float_atan2(y,x)     atan2f(y,x)
 #define sk_float_abs(x)         fabsf(x)
 #define sk_float_copysign(x, y) copysignf(x, y)
@@ skipping 94 matching lines @@
 // This is the number of significant digits we can print in a string such that when we read that
 // string back we get the floating point number we expect.  The minimum value C requires is 6, but
 // most compilers support 9
 #ifdef FLT_DECIMAL_DIG
 #define SK_FLT_DECIMAL_DIG FLT_DECIMAL_DIG
 #else
 #define SK_FLT_DECIMAL_DIG 9
 #endif
 
 #endif