Merge ProgramDesc's for GL and Vulkan

src/gpu/glsl/GrGLSLProgramDesc.h

Index: src/gpu/glsl/GrGLSLProgramDesc.h
diff --git a/src/gpu/glsl/GrGLSLProgramDesc.h b/src/gpu/glsl/GrGLSLProgramDesc.h
new file mode 100644
index 0000000000000000000000000000000000000000..149817988549422935afa0bf827bbb01e9bcb7ab
--- /dev/null
+++ b/src/gpu/glsl/GrGLSLProgramDesc.h
@@ -0,0 +1,63 @@
+/*
+* 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 GrGLSLProgramDesc_DEFINED
+#define GrGLSLProgramDesc_DEFINED
+
+#include "GrColor.h"
+#include "GrProgramDesc.h"
+#include "GrGpu.h"
+#include "GrTypesPriv.h"
+
+class GrGLSLProgramDescBuilder;
+
+class GrGLSLProgramDesc : public GrProgramDesc {
+    friend class GrGLSLProgramDescBuilder;
+};
+
+/**
+* This class can be used to build a GrProgramDesc.  It also provides helpers for accessing
+* GL specific info in the header.
+*/
+class GrGLSLProgramDescBuilder {
+public:
+    typedef GrProgramDesc::KeyHeader KeyHeader;
+    // The key, stored in fKey, is composed of five parts(first 2 are defined in the key itself):
+    // 1. uint32_t for total key length.
+    // 2. uint32_t for a checksum.
+    // 3. Header struct defined above.
+    // 4. Backend-specific information including per-processor keys and their key lengths.
+    //    Each processor's key is a variable length array of uint32_t.
+    enum {
+        // Part 3.
+        kHeaderOffset = GrGLSLProgramDesc::kHeaderOffset,
+        kHeaderSize = SkAlign4(sizeof(KeyHeader)),
+        // Part 4.
+        // This is the offset into the backenend specific part of the key, which includes
+        // per-processor keys.
+        kProcessorKeysOffset = kHeaderOffset + kHeaderSize,
+    };
+
+    /**
+    * Builds a GLSL specific program descriptor
+    *
+    * @param GrPrimitiveProcessor The geometry
+    * @param GrPipeline  The optimized drawstate.  The descriptor will represent a program
+    *                        which this optstate can use to draw with.  The optstate contains
+    *                        general draw information, as well as the specific color, geometry,
+    *                        and coverage stages which will be used to generate the GL Program for
+    *                        this optstate.
+    * @param GrGLSLCaps     Capabilities of the GLSL backend.
+    * @param GrProgramDesc  The built and finalized descriptor
+    **/
+    static bool Build(GrProgramDesc*,
+                      const GrPrimitiveProcessor&,
+                      const GrPipeline&,
+                      const GrGLSLCaps&);
+};
+
+#endif