Add SkRasterPipeline blitter.

src/core/SkCoreBlitters.h

 /*
  * 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.
  */
 
 #ifndef SkCoreBlitters_DEFINED
 #define SkCoreBlitters_DEFINED
 
@@ skipping 192 matching lines @@
        calling the filter, so the blitter can always ignore the colorfilter obj
 
     These pre-conditions must be handled by the caller, in our case
     SkBlitter::Choose(...)
  */
 
 SkBlitter* SkBlitter_ChooseD565(const SkPixmap& device, const SkPaint& paint,
                                 SkShader::Context* shaderContext,
                                 SkTBlitterAllocator* allocator);
 
+
+// Returns nullptr if no SkRasterPipeline blitter can be constructed for this paint.
+SkBlitter* SkCreateRasterPipelineBlitter(const SkPixmap&, const SkPaint&, SkTBlitterAllocator*);
+
 #endif