Add GrPaint stage for xfermodes.

include/gpu/GrPaint.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 GrPaint_DEFINED
@@ skipping 26 matching lines @@
  * pixel is then D' = (1-C)*D + C*(Bd*D + Bs*S).
  *
  * Note that the coverage is applied after the blend. This is why they are computed as distinct
  * values.
  *
  * TODO: Encapsulate setXfermodeColorFilter in a GrEffect and remove from GrPaint.
  */
 class GrPaint {
 public:
     enum {
-        kMaxColorStages     = 2,
+        kMaxColorStages     = 3,
         kMaxCoverageStages  = 1,
     };
 
     GrPaint() { this->reset(); }
 
     GrPaint(const GrPaint& paint) { *this = paint; }
 
     ~GrPaint() {}
 
     /**
@@ skipping 240 matching lines @@
         for (int i = 0; i < kMaxColorStages; ++i) {
             fColorStages[i].reset();
         }
         for (int i = 0; i < kMaxCoverageStages; ++i) {
             fCoverageStages[i].reset();
         }
     }
 };
 
 #endif