Correct SkFixedToDouble.

include/core/SkFixed.h

Index: include/core/SkFixed.h
diff --git a/include/core/SkFixed.h b/include/core/SkFixed.h
index 8cf7a5679ce28358e994114204aba92162bc4332..c2a0a7a4fbf56a30fa5d6026fdb490ab804b5cff 100644
--- a/include/core/SkFixed.h
+++ b/include/core/SkFixed.h
@@ -28,7 +28,7 @@ typedef int32_t             SkFixed;
 #define SK_FixedTanPIOver8  (0x6A0A)
 #define SK_FixedRoot2Over2  (0xB505)
 
-#define SkFixedToFloat(x)   ((x) * 1.5258789e-5f)
+#define SkFixedToFloat(x)   ((x) * 1.52587890625e-5f)

[bungeman-skia, 2015/04/16 20:41:31]

Note that this diff might not cause any change, since I think we got lucky here
and all (current) compilers round the resulting value nicely, mapping this to
the same bit pattern. However, if the compiler didn't round so nicely, the old
value may have been off by one ulp.

 #if 1
     #define SkFloatToFixed(x)   ((SkFixed)((x) * SK_Fixed1))
 #else
@@ -50,7 +50,7 @@ typedef int32_t             SkFixed;
     #define SkFloatToFixed_Check(x) SkFloatToFixed(x)
 #endif
 
-#define SkFixedToDouble(x)  ((x) * 1.5258789e-5)
+#define SkFixedToDouble(x)  ((x) * 1.52587890625e-5)

[bungeman-skia, 2015/04/16 20:41:31]

Note that no one is actually using this at the moment, but we should update this
while it's easy to do so (and I have a test that would like to use it).

 #define SkDoubleToFixed(x)  ((SkFixed)((x) * SK_Fixed1))
 
 /** Converts an integer to a SkFixed, asserting that the result does not overflow