add makeOffset and makeInset to SkRect

include/core/SkRect.h

Index: include/core/SkRect.h
diff --git a/include/core/SkRect.h b/include/core/SkRect.h
index fd8cb16020fd2359ca7435a71be8376ebe850f9c..2c155c477ab46bdc1479f40e215730c61f8e0625 100644
--- a/include/core/SkRect.h
+++ b/include/core/SkRect.h
@@ -157,6 +157,20 @@ struct SK_API SkIRect {
         fRight = fBottom = SK_MinS32;
     }
 
+    /**
+     *  Return a new IRect, built as an offset of this rect.
+     */
+    SkIRect makeOffset(int dx, int dy) const {
+        return MakeLTRB(fLeft + dx, fTop + dy, fRight + dx, fBottom + dy);
+    }
+
+    /**
+     *  Return a new IRect, built as an inset of this rect.
+     */
+    SkIRect makeInset(int dx, int dy) const {
+        return MakeLTRB(fLeft + dx, fTop + dy, fRight - dx, fBottom - dy);
+    }
+
     /** Offset set the rectangle by adding dx to its left and right,
         and adding dy to its top and bottom.
     */
@@ -577,6 +591,20 @@ struct SK_API SkRect {
         fRight = fBottom = SK_ScalarMin;
     }
 
+    /**
+     *  Return a new Rect, built as an offset of this rect.
+     */
+    SkRect makeOffset(SkScalar dx, SkScalar dy) const {
+        return MakeLTRB(fLeft + dx, fTop + dy, fRight + dx, fBottom + dy);
+    }
+
+    /**
+     *  Return a new Rect, built as an inset of this rect.
+     */
+    SkRect makeInset(SkScalar dx, SkScalar dy) const {
+        return MakeLTRB(fLeft + dx, fTop + dy, fRight - dx, fBottom - dy);
+    }
+
     /** Offset set the rectangle by adding dx to its left and right,
         and adding dy to its top and bottom.
     */