Determine whether we can tweakAlphaForCoverage during Pipeline/XP creation.

src/gpu/GrPrimitiveProcessor.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrPrimitiveProcessor_DEFINED
 #define GrPrimitiveProcessor_DEFINED
 
@@ skipping 65 matching lines @@
 /*
  * This struct allows the GrPipeline to communicate information about the pipeline.  Most of this
  * is overrides, but some of it is general information.  Logically it should live in GrPipeline.h,
  * but this is problematic due to circular dependencies.
  */
 struct GrPipelineInfo {
     bool fColorIgnored;
     bool fCoverageIgnored;
     GrColor fOverrideColor;
     bool fUsesLocalCoords;
+    bool fCanTweakAlphaForCoverage;
 };
 
 /*
  * This enum is shared by GrPrimitiveProcessors and GrGLPrimitiveProcessors to coordinate shaders
  * with vertex attributes / uniforms.
  */
 enum GrGPInput {
     kAllOnes_GrGPInput,
     kAttribute_GrGPInput,
     kUniform_GrGPInput,
@@ skipping 125 matching lines @@
     virtual bool hasExplicitLocalCoords() const = 0;
 
     const SkMatrix fViewMatrix;
     SkMatrix fLocalMatrix;
     bool fIsPathRendering;
 
     typedef GrProcessor INHERITED;
 };
 
 #endif