Optimize 9patch rendering.

This change detects empty quads in 9patches and removes them from
the mesh to avoid unnecessary blending.

Change-Id: I4500566fb4cb6845d64dcb59b522c0be7a0ec704
diff --git a/libs/hwui/OpenGLRenderer.h b/libs/hwui/OpenGLRenderer.h
index 4caa8fb..9900a27 100644
--- a/libs/hwui/OpenGLRenderer.h
+++ b/libs/hwui/OpenGLRenderer.h
@@ -101,8 +101,8 @@
             float srcRight, float srcBottom, float dstLeft, float dstTop,
             float dstRight, float dstBottom, const SkPaint* paint);
     virtual void drawPatch(SkBitmap* bitmap, const int32_t* xDivs, const int32_t* yDivs,
-            uint32_t width, uint32_t height, float left, float top, float right, float bottom,
-            const SkPaint* paint);
+            const uint32_t* colors, uint32_t width, uint32_t height, int8_t numColors,
+            float left, float top, float right, float bottom, const SkPaint* paint);
     virtual void drawColor(int color, SkXfermode::Mode mode);
     virtual void drawRect(float left, float top, float right, float bottom, const SkPaint* paint);
     virtual void drawPath(SkPath* path, SkPaint* paint);