Implement support for mixed sampled render targets

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 462 matching lines @@
     /** IDs for copy surface program. */
     struct {
         GrGLuint    fProgram;
         GrGLint     fTextureUniform;
         GrGLint     fTexCoordXformUniform;
         GrGLint     fPosXformUniform;
         GrGLuint    fArrayBuffer;
     } fCopyProgram;
 
     TriState fMSAAEnabled;
+    TriState fCoverageModulationEnabled;

[Chris Dalton, 2015/06/09 17:39:52]

After discussions with the hardware guys, we can just leave coverage modulation
always enabled rather than tracking its state. It has no effect when not using
mixed samples.

 
     GrStencilSettings           fHWStencilSettings;
     TriState                    fHWStencilTestEnabled;
 
 
     GrPipelineBuilder::DrawFace fHWDrawFace;
     TriState                    fHWWriteToColor;
     TriState                    fHWDitherEnabled;
     uint32_t                    fHWBoundRenderTargetUniqueID;
     SkTArray<uint32_t, true>    fHWBoundTextureUniqueIDs;
 
     ///@}
 
     // 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