cc: Create a Region class that wraps SkRegion, to replace use of WebCore::Region.

cc/math_util.h

Index: cc/math_util.h
diff --git a/cc/math_util.h b/cc/math_util.h
index 1caf6595c0a8483335ae6784c94e8d1bee567c68..fe1780042800f53800b9e8b1a19f2b2daf782644 100644
--- a/cc/math_util.h
+++ b/cc/math_util.h
@@ -67,6 +67,14 @@ struct HomogeneousCoordinate {
 
 class CC_EXPORT MathUtil {
 public:
+    static const double PI_DOUBLE;
+    static const float PI_FLOAT;
+
+    static double Deg2Rad(double deg)  { return deg * PI_DOUBLE / 180; }
+    static double Rad2Deg(double rad)  { return rad * 180 / PI_DOUBLE; }
+
+    static float Deg2Rad(float deg)  { return deg * PI_FLOAT / 180; }
+    static float Rad2Deg(float rad)  { return rad * 180 / PI_FLOAT; }
 
     // Background: WebTransformationMatrix code in WebCore does not do the right thing in
     // mapRect / mapQuad / projectQuad when there is a perspective projection that causes