refactor parts of SkGr.cpp for use by SkImages

src/gpu/GrYUVProvider.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 GrYUVScoper_DEFINED
+#define GrYUVScoper_DEFINED
+
+#include "GrTypes.h"
+#include "SkImageInfo.h"
+
+class GrContext;
+class GrTexture;
+
+class GrYUVProvider {
+public:
+    virtual ~GrYUVProvider() {}
+
+    GrTexture* refAsTexture(GrContext*, const GrSurfaceDesc&, bool useCache);
+
+    virtual uint32_t onGetID() = 0;
+    virtual bool onGetYUVSizes(SkISize sizes[3]) = 0;

[joshualitt, 2015/09/04 15:16:13]

constant kNumYUVPlanes?

+    virtual bool onGetYUVPlanes(SkISize sizes[3], void* planes[3], size_t rowBytes[3],
+                                SkYUVColorSpace*) = 0;
+};
+
+#endif