Rename ShaderType enum to ShaderVisibility

Renames ShaderType in GrGLShaderBuilder to ShaderVisibility. It is now
used solely as a bitfield. Methods that previously accepted a single
ShaderType value are split into separate calls:

 - getShader -> vsGetShader, gsGetShader, fsGetShader
 - emiitFunction -> fsEmitFunction
 - appendTextureLookup -> fsAppendTextureLookup

No change in functionality. This is a refactoring to allow us to
separate the vertex/geometry and fragment parts of GrGLShaderBuilder.

R=bsalomon@google.com

Author: cdalton@nvidia.com

Review URL: https://chromiumcodereview.appspot.com/23826002

git-svn-id: http://skia.googlecode.com/svn/trunk@11044 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkArithmeticMode.cpp b/src/effects/SkArithmeticMode.cpp
index 1efa115..fd81d82 100644
--- a/src/effects/SkArithmeticMode.cpp
+++ b/src/effects/SkArithmeticMode.cpp
@@ -354,10 +354,7 @@
         SkString bgCoords;
         GrSLType bgCoordsType = fBackgroundEffectMatrix.emitCode(builder, key, &bgCoords, NULL, "BG");
         builder->fsCodeAppend("\t\tvec4 bgColor = ");
-        builder->appendTextureLookup(GrGLShaderBuilder::kFragment_ShaderType,
-                                     samplers[0],
-                                     bgCoords.c_str(),
-                                     bgCoordsType);
+        builder->fsAppendTextureLookup(samplers[0], bgCoords.c_str(), bgCoordsType);
         builder->fsCodeAppendf(";\n");
         dstColor = "bgColor";
     } else {
@@ -365,7 +362,7 @@
     }
 
     SkASSERT(NULL != dstColor);
-    fKUni = builder->addUniform(GrGLShaderBuilder::kFragment_ShaderType,
+    fKUni = builder->addUniform(GrGLShaderBuilder::kFragment_Visibility,
                                 kVec4f_GrSLType, "k");
     const char* kUni = builder->getUniformCStr(fKUni);