Add BoxF::ExpandTo

ui/gfx/box_f.h

Index: ui/gfx/box_f.h
diff --git a/ui/gfx/box_f.h b/ui/gfx/box_f.h
index fb2c1910a96ebe18375ab8eee821f136ea0b51a5..e1b8c089d2ee6162e41e00731440bcf4b3bba7f3 100644
--- a/ui/gfx/box_f.h
+++ b/ui/gfx/box_f.h
@@ -94,7 +94,15 @@ class GFX_EXPORT BoxF {
   const Point3F& origin() const { return origin_; }
   void set_origin(const Point3F& origin) { origin_ = origin; }
 
+  // Expands the box to contain the given point, if necessary.

[danakj, 2013/10/01 14:23:44]

Can you also comment on what this function does if the current box is empty?

+  void ExpandTo(const Point3F& point);
+
  private:
+  // Expands the box to contain the two given points. It is guaranteed that each

[danakj, 2013/10/01 14:23:44]

s/guaranteed/required/

+  // component of |min| is less than or equal to the corresponding component in
+  // |max|.
+  void ExpandTo(const Point3F& min, const Point3F& max);
+
   Point3F origin_;
   float width_;
   float height_;