Add XferProcessor factory in GrPaint and GrDrawState.

src/gpu/gl/GrGLXferProcessor.h

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef GrGLXferProcessor_DEFINED
+#define GrGLXferProcessor_DEFINED
+
+#if 0 // Can undo this once I have a backend. Remove GrGLXferProcessor from gl/GrGLProcessor.h"
+#include "GrGLProcessor.h"
+
+class GrGLFPBuilder;
+
+/**

[bsalomon, 2014/11/26 21:02:45]

All the comments in this file seem to be related to GrGLGeometryProcessor

[egdaniel, 2014/12/01 18:18:25]

This file is actually not even needed till the final cl so I am just going to
delete it for now

+ * If a GL effect needs a GrGLFullShaderBuilder* object to emit vertex code, then it must inherit
+ * from this class. Since paths don't have vertices, this class is only meant to be used internally
+ * by skia, for special cases.
+ */
+class GrGLXferProcessor : public GrGLProcessor {
+public:
+    GrGLXferProcessor(const GrBackendProcessorFactory& factory)
+        : INHERITED(factory) {}
+
+    /**
+     * This is similar to emitCode() in the base class, except it takes a full shader builder.
+     * This allows the effect subclass to emit vertex code.
+     */
+    virtual void emitCode(GrGLFPBuilder* builder,
+                          const GrXferProcessor& xferProcessor,
+                          const GrProcessorKey& key,
+                          const char* outputColor,
+                          const char* inputColor,
+                          const TransformedCoordsArray& coords,
+                          const TextureSamplerArray& samplers) = 0;
+
+private:
+    typedef GrGLProcessor INHERITED;
+};
+#endif
+#endif