Update Skia's YUV API

include/core/SkYUVSizeInfo.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 SkYUVSizeInfo_DEFINED
+#define SkYUVSizeInfo_DEFINED
+
+struct SkYUVSizeInfo {
+    enum {
+        kY          = 0,
+        kU          = 1,
+        kV          = 2,
+        kPlaneCount = 3,

[reed1, 2016/02/19 22:00:23]

nit: In general we have shied away from placing the "count" in the same enum as
"indices", since its slightly suggestive of a client using it as an index!

Personally I think its fine to just use [3] here, since YUV isn't going to
change EVER. If you prefer a named value, how about a separate enum somewhere,
so it is visually separate from Y U V...?

[msarett, 2016/02/19 22:16:12]

Makes sense.  No reason not to just use 3 :).

+    };
+    SkISize fSizes[kPlaneCount];
+
+    /**
+     * While the widths of the Y, U, and V planes are not restricted, the
+     * implementation often requires that the width of the memory allocated
+     * for each plane be a multiple of 8.
+     *
+     * This struct allows us to inform the client how many "widthBytes"
+     * that we need.  Note that we use the new idea of "widthBytes"
+     * because this idea is distinct from "rowBytes" (used elsewhere in
+     * Skia).  "rowBytes" allow the last row of the allocation to not
+     * include any extra padding, while, in this case, every single row of
+     * the allocation must be at least "widthBytes".
+     */
+    size_t fWidthBytes[kPlaneCount];
+};
+
+#endif // SkYUVSizeInfo_DEFINED