Initial linear gradient 4f impl

src/effects/gradients/SkLinearGradient.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkLinearGradient_DEFINED
 #define SkLinearGradient_DEFINED
 
 #include "SkGradientShaderPriv.h"
 #include "SkNx.h"
 
 struct Sk4fStorage {
     float fArray[4];
 
     operator Sk4f() const {
         return Sk4f::Load(fArray);
     }
 
     Sk4fStorage& operator=(const Sk4f& src) {
         src.store(fArray);
         return *this;
     }
 };
 
 class SkLinearGradient : public SkGradientShaderBase {
 public:
+    enum {
+        // Temp flag for testing the 4f impl.
+        kForce4fContext_PrivateFlag     = 1 << 7,
+    };
+
     SkLinearGradient(const SkPoint pts[2], const Descriptor&);
 
     size_t contextSize() const override;
 
     class LinearGradientContext : public SkGradientShaderBase::GradientShaderBaseContext {
     public:
         LinearGradientContext(const SkLinearGradient&, const ContextRec&);
 
         void shadeSpan(int x, int y, SkPMColor dstC[], int count) override;
 
@@ skipping 23 matching lines @@
 
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkLinearGradient)
 
 protected:
     SkLinearGradient(SkReadBuffer& buffer);
     void flatten(SkWriteBuffer& buffer) const override;
     Context* onCreateContext(const ContextRec&, void* storage) const override;
 
 private:
+    class LinearGradient4fContext;
+
     friend class SkGradientShader;
     typedef SkGradientShaderBase INHERITED;
     const SkPoint fStart;
     const SkPoint fEnd;
 };
 
 #endif