Potentially optimize some GrGLEffects for known input color values

src/gpu/gl/GrGLShaderBuilder.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLShaderBuilder_DEFINED
 #define GrGLShaderBuilder_DEFINED
 
@@ skipping 72 matching lines @@
     /** Version of above that appends the result to the fragment shader code instead.*/
     void fsAppendTextureLookup(const TextureSampler&,
                                const char* coordName,
                                GrSLType coordType = kVec2f_GrSLType);
 
 
     /** Does the work of appendTextureLookup and modulates the result by modulation. The result is
         always a vec4. modulation and the swizzle specified by TextureSampler must both be vec4 or
         float. If modulation is "" or NULL it this function acts as though appendTextureLookup were
         called. */
-    void fsAppendTextureLookupAndModulate(const char* modulation,
+    void fsAppendTextureLookupAndModulate(const GrGLSLExpr4& modulation,
                                           const TextureSampler&,
                                           const char* coordName,
                                           GrSLType coordType = kVec2f_GrSLType);
 
     /** Emits a helper function outside of main() in the fragment shader. */
     void fsEmitFunction(GrSLType returnType,
                         const char* name,
                         int argCnt,
                         const GrGLShaderVar* args,
                         const char* body,
@@ skipping 343 matching lines @@
                 int effectCnt,
                 GrGLSLExpr4* inOutFSColor) SK_OVERRIDE;
 
 private:
     int fNumTexCoordSets;
 
     typedef GrGLShaderBuilder INHERITED;
 };
 
 #endif