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/GrTextureDomainEffect.cpp b/src/gpu/effects/GrTextureDomainEffect.cpp
index 1bf0512..e76d0c9 100644
--- a/src/gpu/effects/GrTextureDomainEffect.cpp
+++ b/src/gpu/effects/GrTextureDomainEffect.cpp
@@ -27,7 +27,7 @@
                          const GrRenderTarget*,
                          int stageNum) SK_OVERRIDE;
 
-    static inline StageKey GenKey(const GrCustomStage&) { return 0; }
+    static inline StageKey GenKey(const GrCustomStage&, const GrGLCaps&) { return 0; }
 
 private:
     GrGLUniformManager::UniformHandle fNameUni;
@@ -107,5 +107,3 @@
     const GrTextureDomainEffect& s = static_cast<const GrTextureDomainEffect&>(sBase);
     return (INHERITED::isEqual(sBase) && this->fTextureDomain == s.fTextureDomain);
 }
-
-