Set up cache in vulkan to reuse GrVkPrograms (aka VkPipelines)

src/gpu/vk/GrVkVaryingHandler.h

 /*
 * Copyright 2016 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
 
 #ifndef GrVkVaryingHandler_DEFINED
 #define GrVkVaryingHandler_DEFINED
 
 #include "glsl/GrGLSLVarying.h"
 
 class GrVkVaryingHandler : public GrGLSLVaryingHandler {
 public:
     GrVkVaryingHandler(GrGLSLProgramBuilder* program) : INHERITED(program) {}
 
     typedef GrGLSLVaryingHandler::VarArray VarArray;
 
 private:
     void onFinalize() override;
 
-    friend class GrVkProgramBuilder;
+    friend class GrVkPipelineStateBuilder;
 
     typedef GrGLSLVaryingHandler INHERITED;
 };
 
-#endif
+#endif