add sample for arcTo

include/core/SkRect.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkRect_DEFINED
 #define SkRect_DEFINED
 
@@ skipping 674 matching lines @@
 
 public:
     /**
      *  Return true if this rectangle is not empty, and the specified sides of
      *  a rectangle are not empty, and they intersect.
      */
     bool intersects(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom) const {
         return Intersects(fLeft, fTop, fRight, fBottom, left, top, right, bottom);
     }
 
+    bool intersects(const SkRect& r) const {
+        return Intersects(fLeft, fTop, fRight, fBottom,
+                          r.fLeft, r.fTop, r.fRight, r.fBottom);
+    }
+
     /**
      *  Return true if rectangles a and b are not empty and intersect.
      */
     static bool Intersects(const SkRect& a, const SkRect& b) {
         return Intersects(a.fLeft, a.fTop, a.fRight, a.fBottom,
                           b.fLeft, b.fTop, b.fRight, b.fBottom);
     }
 
     /**
      *  Update this rectangle to enclose itself and the specified rectangle.
@@ skipping 162 matching lines @@
      *  cast-safe way to treat the rect as an array of (4) SkScalars.
      */
     const SkScalar* asScalars() const { return &fLeft; }
 
     void dump(bool asHex) const;
     void dump() const { this->dump(false); }
     void dumpHex() const { this->dump(true); }
 };
 
 #endif