Introduction of set of functions to manage generation of texture fetch shader code.  

A new set of routines have been added to GrGLShaderBuilder to emit texture fetches, taking into consideration the format of the texture to be accessed, and the channel swizzle.  
Review URL: https://codereview.appspot.com/6446072

git-svn-id: http://skia.googlecode.com/svn/trunk@4919 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/effects/GrSingleTextureEffect.cpp b/src/gpu/effects/GrSingleTextureEffect.cpp
index 350d9e6..5f66e09 100644
--- a/src/gpu/effects/GrSingleTextureEffect.cpp
+++ b/src/gpu/effects/GrSingleTextureEffect.cpp
@@ -26,7 +26,7 @@
         builder->emitDefaultFetch(outputColor, samplerName);
     }
 
-    static inline StageKey GenKey(const GrCustomStage&) { return 0; }
+    static inline StageKey GenKey(const GrCustomStage&, const GrGLCaps&) { return 0; }
 
 private:
 
@@ -56,5 +56,3 @@
 const GrProgramStageFactory& GrSingleTextureEffect::getFactory() const {
     return GrTProgramStageFactory<GrSingleTextureEffect>::getInstance();
 }
-
-