Use float rather than SkFixed for gradient TileProcs.

src/effects/gradients/SkGradientShaderPriv.h

Index: src/effects/gradients/SkGradientShaderPriv.h
diff --git a/src/effects/gradients/SkGradientShaderPriv.h b/src/effects/gradients/SkGradientShaderPriv.h
index 5b1b09b9fccece7273a90d25d3414c00f8788523..ef16250dc189fa583b39b12b9c3dcddf7b99c414 100644
--- a/src/effects/gradients/SkGradientShaderPriv.h
+++ b/src/effects/gradients/SkGradientShaderPriv.h
@@ -8,6 +8,8 @@
 #ifndef SkGradientShaderPriv_DEFINED
 #define SkGradientShaderPriv_DEFINED
 
+#include "math.h"
+
 #include "SkGradientBitmapCache.h"
 #include "SkGradientShader.h"
 #include "SkClampRange.h"
@@ -39,14 +41,23 @@ static inline void sk_memset32_dither(uint32_t dst[], uint32_t v0, uint32_t v1,
 
 //  Clamp
 
-static inline SkFixed clamp_tileproc(SkFixed x) {
-    return SkClampMax(x, 0xFFFF);
+static inline unsigned clamp_tileproc(float x) {
+    unsigned result = (unsigned)(0xFFFF * SkTPin(x, 0.0f, 1.0f));
+    if (result > 0xFFFF) {
+      SkDebugf("clamp_tileproc: x: %f  result: %d\n", x, result);
+    }
+    return result;
 }
 
 // Repeat
 
-static inline SkFixed repeat_tileproc(SkFixed x) {
-    return x & 0xFFFF;
+static inline unsigned repeat_tileproc(float x) {
+    float modulo = fmod(x, 1.0f);
+    unsigned result = (unsigned)(0xFFFF * modulo);
+    if (result > 0xFFFF) {
+      SkDebugf("repeat_tileproc: x: %f  modulo: %f  result: %d\n", x, modulo, result);
+    }
+    return result;
 }
 
 // Mirror
@@ -57,9 +68,17 @@ static inline SkFixed repeat_tileproc(SkFixed x) {
 #pragma optimize("", off)
 #endif
 
-static inline SkFixed mirror_tileproc(SkFixed x) {
-    int s = SkLeftShift(x, 15) >> 31;
-    return (x ^ s) & 0xFFFF;
+static inline unsigned mirror_tileproc(float x) {
+    const float x_mod_2 = fmod(x, 2.0f);
+    int x_17bits = (int)(x_mod_2 * 0x10000);
+    if (x_17bits & 0x10000) {
+        x_17bits = ~x_17bits;
+    }
+    unsigned result = x_17bits & 0xFFFF;
+    if (result > 0xFFFF) {
+      SkDebugf("mirror_tileproc: x: %f  x_mod_2: %f  x_17bits: %d  result: %d\n", x, x_mod_2, x_17bits, result);
+    }
+    return result;
 }
 
 #if defined(_MSC_VER) && (_MSC_VER >= 1600)
@@ -68,7 +87,7 @@ static inline SkFixed mirror_tileproc(SkFixed x) {
 
 ///////////////////////////////////////////////////////////////////////////////
 
-typedef SkFixed (*TileProc)(SkFixed);
+typedef unsigned (*TileProc)(float);
 
 ///////////////////////////////////////////////////////////////////////////////