Adds function to invert a transform to ui::Transform
Required for http://codereview.chromium.org/8368013/

BUG= None
TEST= None

Review URL: http://codereview.chromium.org/8383006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@106992 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/ui/gfx/transform.h b/ui/gfx/transform.h
index 483aa564..4f830d5 100644
--- a/ui/gfx/transform.h
+++ b/ui/gfx/transform.h
@@ -69,6 +69,9 @@
   // Does the transformation change anything?
   bool HasChange() const;
 
+  // Inverts the transform which is passed in. Returns true if successful.
+  bool GetInverse(Transform* transform) const;
+
   // Applies the transformation on the point. Returns true if the point is
   // transformed successfully.
   void TransformPoint(gfx::Point3f& point) const;