create struct to hold all the params passed around for shader::context

src/effects/gradients/SkLinearGradient.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLinearGradient.h"
 
 static inline int repeat_bits(int x, const int bits) {
@@ skipping 58 matching lines @@
 void SkLinearGradient::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
     buffer.writePoint(fStart);
     buffer.writePoint(fEnd);
 }
 
 size_t SkLinearGradient::contextSize() const {
     return sizeof(LinearGradientContext);
 }
 
-SkShader::Context* SkLinearGradient::createContext(const SkBitmap& device, const SkPaint& paint,
-                                                   const SkMatrix& matrix, void* storage) const {
-    if (!this->validContext(device, paint, matrix)) {
+SkShader::Context* SkLinearGradient::createContext(const ContextRec& rec, void* storage) const {
+    if (!this->validContext(rec)) {
         return NULL;
     }
 
-    return SkNEW_PLACEMENT_ARGS(storage, LinearGradientContext, (*this, device, paint, matrix));
+    return SkNEW_PLACEMENT_ARGS(storage, LinearGradientContext, (*this, rec));
 }
 
 SkLinearGradient::LinearGradientContext::LinearGradientContext(
-        const SkLinearGradient& shader, const SkBitmap& device,
-        const SkPaint& paint, const SkMatrix& matrix)
-    : INHERITED(shader, device, paint, matrix)
+        const SkLinearGradient& shader, const ContextRec& rec)
+    : INHERITED(shader, rec)
 {
     unsigned mask = SkMatrix::kTranslate_Mask | SkMatrix::kScale_Mask;
     if ((fDstToIndex.getType() & ~mask) == 0) {
         // when we dither, we are (usually) not const-in-Y
-        if ((fFlags & SkShader::kHasSpan16_Flag) && !paint.isDither()) {
+        if ((fFlags & SkShader::kHasSpan16_Flag) && !rec.fPaint->isDither()) {
             // only claim this if we do have a 16bit mode (i.e. none of our
             // colors have alpha), and if we are not dithering (which obviously
             // is not const in Y).
             fFlags |= SkShader::kConstInY16_Flag;
         }
     }
 }
 
 #define NO_CHECK_ITER               \
     do {                            \
@@ skipping 470 matching lines @@
     str->append("SkLinearGradient (");
 
     str->appendf("start: (%f, %f)", fStart.fX, fStart.fY);
     str->appendf(" end: (%f, %f) ", fEnd.fX, fEnd.fY);
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif