Initial implementation of GPU no filter NinePatch

include/gpu/GrDrawContext.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 GrDrawContext_DEFINED
 #define GrDrawContext_DEFINED
 
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      * @param oval          the bounding rect of the oval.
      * @param strokeInfo    the stroke information (width, join, cap) and
      *                      the dash information (intervals, count, phase).
      */
     void drawOval(const GrClip&,
                   const GrPaint& paint,
                   const SkMatrix& viewMatrix,
                   const SkRect& oval,
                   const GrStrokeInfo& strokeInfo);
 
+    /**
+     *  Draw the image stretched differentially to fit into dst.
+     *  center is a rect within the image, and logically divides the image
+     *  into 9 sections (3x3). For example, if the middle pixel of a [5x5]
+     *  image is the "center", then the center-rect should be [2, 2, 3, 3].
+     *
+     *  If the dst is >= the image size, then...
+     *  - The 4 corners are not stretched at all.
+     *  - The sides are stretched in only one axis.
+     *  - The center is stretched in both axes.
+     * Else, for each axis where dst < image,
+     *  - The corners shrink proportionally
+     *  - The sides (along the shrink axis) and center are not drawn
+     */
+    void drawImageNine(const GrClip&,
+                       const GrPaint& paint,
+                       const SkMatrix& viewMatrix,
+                       int imageWidth,
+                       int imageHeight,
+                       const SkIRect& center,
+                       const SkRect& dst);
 
     /**
      * Draws a batch
      *
      * @param paint    describes how to color pixels.
      * @param batch    the batch to draw
      */
     void drawBatch(const GrClip&, const GrPaint&, GrDrawBatch*);
 
 private:
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     // In MDB-mode the drawTarget can be closed by some other drawContext that has picked
     // it up. For this reason, the drawTarget should only ever be accessed via 'getDrawTarget'.
     GrDrawTarget*     fDrawTarget;
     GrTextContext*    fTextContext; // lazily gotten from GrContext::DrawingManager
 
     SkSurfaceProps    fSurfaceProps;
 };
 
 #endif