Refactor read and write buffers.

src/core/SkDraw.cpp

 /*
  * 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.
  */
 
 #include "SkDraw.h"
 #include "SkBlitter.h"
 #include "SkBounder.h"
@@ skipping 2364 matching lines @@
     SkTriColorShader() {}
 
     bool setup(const SkPoint pts[], const SkColor colors[], int, int, int);
 
     virtual void shadeSpan(int x, int y, SkPMColor dstC[], int count) SK_OVERRIDE;
 
     SK_DEVELOPER_TO_STRING()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkTriColorShader)
 
 protected:
-    SkTriColorShader(SkFlattenableReadBuffer& buffer) : SkShader(buffer) {}
+    SkTriColorShader(SkReadBuffer& buffer) : SkShader(buffer) {}
 
 private:
     SkMatrix    fDstToUnit;
     SkPMColor   fColors[3];
 
     typedef SkShader INHERITED;
 };
 
 bool SkTriColorShader::setup(const SkPoint pts[], const SkColor colors[],
                              int index0, int index1, int index2) {
@@ skipping 424 matching lines @@
         mask->fImage = SkMask::AllocImage(size);
         memset(mask->fImage, 0, mask->computeImageSize());
     }
 
     if (SkMask::kJustComputeBounds_CreateMode != mode) {
         draw_into_mask(*mask, devPath, style);
     }
 
     return true;
 }