Make gfx::Rect class operations consistently mutate the class they are called on.

ui/gfx/rect.h

Index: ui/gfx/rect.h
diff --git a/ui/gfx/rect.h b/ui/gfx/rect.h
index 7d73f4d8a6a54145e82dd894e28d595ae43c667c..2eab239d4bc76d948c93b86606622841fe778b39 100644
--- a/ui/gfx/rect.h
+++ b/ui/gfx/rect.h
@@ -64,15 +64,6 @@ class UI_EXPORT Rect : public RectBase<Rect, Point, Size, Insets, int> {
     return RectF(origin().x(), origin().y(), size().width(), size().height());
   }
 
-  RectF Scale(float scale) const WARN_UNUSED_RESULT {
-    return Scale(scale, scale);
-  }
-
-  RectF Scale(float x_scale, float y_scale) const WARN_UNUSED_RESULT {
-    RectF original = *this;
-    return original.Scale(x_scale, y_scale);
-  }
-
   std::string ToString() const;
 };