Move shader compiling to ProgramBuilder and various ShaderBuilder cleanups.

src/gpu/gl/GrGLProgramDesc.cpp

Index: src/gpu/gl/GrGLProgramDesc.cpp
diff --git a/src/gpu/gl/GrGLProgramDesc.cpp b/src/gpu/gl/GrGLProgramDesc.cpp
index 281f2c06a6241ef92b77c56184a4f30c17d9dcd2..a232a635148adcd1b13ff3b60412c728ee676200 100644
--- a/src/gpu/gl/GrGLProgramDesc.cpp
+++ b/src/gpu/gl/GrGLProgramDesc.cpp
@@ -159,8 +159,7 @@ bool GrGLProgramDescBuilder::Build(GrProgramDesc* desc,
 
     if (pipeline.readsFragPosition()) {
         header->fFragPosKey =
-                GrGLFragmentShaderBuilder::KeyForFragmentPosition(pipeline.getRenderTarget(),
-                                                                  gpu->glCaps());
+                GrGLFragmentShaderBuilder::KeyForFragmentPosition(pipeline.getRenderTarget());
     } else {
         header->fFragPosKey = 0;
     }