Implement support for KHR_blend_equation_advanced

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
 
@@ skipping 419 matching lines @@
         // We return a non-const pointer to this from bindArrayAndBuffersToDraw when vertex array 0
         // is bound. However, this class is internal to GrGLGpu and this object never leaks out of
         // GrGLGpu.
         GrGLAttribArrayState    fDefaultVertexArrayAttribState;
 
         // This is used when we're using a core profile and the vertices are in a VBO.
         GrGLVertexArray*        fVBOVertexArray;
     } fHWGeometryState;
 
     struct {
+        GrBlendEquation fEquation;
         GrBlendCoeff    fSrcCoeff;
         GrBlendCoeff    fDstCoeff;
         GrColor         fConstColor;
         bool            fConstColorValid;
         TriState        fEnabled;
 
         void invalidate() {
+            fEquation = kInvalid_GrBlendEquation;
             fSrcCoeff = kInvalid_GrBlendCoeff;
             fDstCoeff = kInvalid_GrBlendCoeff;
             fConstColorValid = false;
             fEnabled = kUnknown_TriState;
         }
     } fHWBlendState;
 
     TriState fMSAAEnabled;
 
     GrStencilSettings           fHWStencilSettings;
@@ skipping 10 matching lines @@
 
     // we record what stencil format worked last time to hopefully exit early
     // from our loop that tries stencil formats and calls check fb status.
     int fLastSuccessfulStencilFmtIdx;
 
     typedef GrGpu INHERITED;
     friend class GrGLPathRendering; // For accessing setTextureUnit.
 };
 
 #endif