Create GrGLSLVaryingHandler class for program building

src/gpu/gl/GrGLVaryingHandler.h

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrGLVaryingHandler_DEFINED
+#define GrGLVaryingHandler_DEFINED
+
+#include "glsl/GrGLSLVarying.h"
+#include "GrTypesPriv.h"
+#include "gl/GrGLProgramDataManager.h"
+
+class GrGLVaryingHandler : public GrGLSLVaryingHandler {
+public:
+    GrGLVaryingHandler(GrGLSLProgramBuilder* program)
+        : INHERITED(program),
+        fPathProcVaryingInfos(kVaryingsPerBlock) {}
+
+    // This function is used by the NVPR PathProcessor to add a varying directly into the fragment
+    // shader since there is no vertex shader.
+    VaryingHandle addPathProcessingVarying(const char* name, GrGLSLVertToFrag*,
+                                       GrSLPrecision fsPrecision = kDefault_GrSLPrecision);
+
+private:
+    typedef GrGLProgramDataManager::VaryingInfo VaryingInfo;
+    typedef GrGLProgramDataManager::VaryingInfoArray VaryingInfoArray;
+
+    VaryingInfoArray fPathProcVaryingInfos;
+
+    friend class GrGLProgramBuilder;
+
+    typedef GrGLSLVaryingHandler INHERITED; 
+};
+
+#endif
+