Swizzle shader output and blend when using GL_RED to implement kAlpha_8_GrPixelConfig

src/gpu/gl/GrGLGpu.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLGpu_DEFINED
 #define GrGLGpu_DEFINED
 
 #include "GrGLContext.h"
 #include "GrGLIRect.h"
 #include "GrGLIndexBuffer.h"
 #include "GrGLPathRendering.h"
 #include "GrGLProgram.h"
 #include "GrGLRenderTarget.h"
 #include "GrGLStencilAttachment.h"
 #include "GrGLTexture.h"
 #include "GrGLTransferBuffer.h"
 #include "GrGLVertexArray.h"
 #include "GrGLVertexBuffer.h"
 #include "GrGpu.h"
 #include "GrPipelineBuilder.h"
 #include "GrXferProcessor.h"
 #include "SkTypes.h"
 
 class GrPipeline;
 class GrNonInstancedVertices;
+class GrSwizzle;
 
 #ifdef SK_DEVELOPER
 #define PROGRAM_CACHE_STATS
 #endif
 
 class GrGLGpu : public GrGpu {
 public:
     static GrGpu* Create(GrBackendContext backendContext, const GrContextOptions& options,
                          GrContext* context);
     ~GrGLGpu() override;
@@ skipping 153 matching lines @@
     // Flushes state from GrPipeline to GL. Returns false if the state couldn't be set.
     bool flushGLState(const DrawArgs&);
 
     // Sets up vertex attribute pointers and strides. On return indexOffsetInBytes gives the offset
     // an into the index buffer. It does not account for vertices.startIndex() but rather the start
     // index is relative to the returned offset.
     void setupGeometry(const GrPrimitiveProcessor&,
                        const GrNonInstancedVertices& vertices,
                        size_t* indexOffsetInBytes);
 
-    // Subclasses should call this to flush the blend state.
-    void flushBlend(const GrXferProcessor::BlendInfo& blendInfo);
+    void flushBlend(const GrXferProcessor::BlendInfo& blendInfo, const GrSwizzle&);
 
     bool hasExtension(const char* ext) const { return fGLContext->hasExtension(ext); }
 
     void copySurfaceAsDraw(GrSurface* dst,
                            GrSurface* src,
                            const SkIRect& srcRect,
                            const SkIPoint& dstPoint);
     void copySurfaceAsCopyTexSubImage(GrSurface* dst,
                                       GrSurface* src,
                                       const SkIRect& srcRect,
@@ skipping 327 matching lines @@
             SkASSERT(target == GR_GL_TEXTURE_EXTERNAL);
             return 1;
         }
     }
 
     typedef GrGpu INHERITED;
     friend class GrGLPathRendering; // For accessing setTextureUnit.
 };
 
 #endif