Add SkColor4f serialization

src/core/SkColorShader.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorShader.h"
 #include "SkColorSpace.h"
 #include "SkReadBuffer.h"
@@ skipping 112 matching lines @@
 }
 
 SkColor4Shader::SkColor4Shader(const SkColor4f& color, sk_sp<SkColorSpace> space)
     : fColorSpace(std::move(space))
     , fColor4(color)
     , fCachedByteColor(unit_to_skcolor(color.pin(), space.get()))
 {}
 
 sk_sp<SkFlattenable> SkColor4Shader::CreateProc(SkReadBuffer& buffer) {
     SkColor4f color;
-    color.fR = buffer.readScalar(); // readFloat()
-    color.fG = buffer.readScalar();
-    color.fB = buffer.readScalar();
-    color.fA = buffer.readScalar();
+    buffer.readColor4f(&color);
     if (buffer.readBool()) {
         // TODO how do we unflatten colorspaces
     }
     return SkShader::MakeColorShader(color, nullptr);
 }
 
 void SkColor4Shader::flatten(SkWriteBuffer& buffer) const {
-    buffer.writeScalar(fColor4.fR); // writeFloat()
-    buffer.writeScalar(fColor4.fG);
-    buffer.writeScalar(fColor4.fB);
-    buffer.writeScalar(fColor4.fA);
+    buffer.writeColor4f(fColor4);
     buffer.writeBool(false);    // TODO how do we flatten colorspaces?
 }
 
 uint32_t SkColor4Shader::Color4Context::getFlags() const {
     return fFlags;
 }
 
 SkShader::Context* SkColor4Shader::onCreateContext(const ContextRec& rec, void* storage) const {
     return new (storage) Color4Context(*this, rec);
 }
@@ skipping 142 matching lines @@
 }
 
 bool SkColorShader::ColorShaderContext::onChooseBlitProcs(const SkImageInfo& info,
                                                           BlitState* state) {
     return choose_blitprocs(&fPM4f, info, state);
 }
 
 bool SkColor4Shader::Color4Context::onChooseBlitProcs(const SkImageInfo& info, BlitState* state) {
     return choose_blitprocs(&fPM4f, info, state);
 }