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

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index 5f81c5ff9fb0edbe32e21b7060ef569c1e856482..1174e07178f30886480104745ccd680ed7df6188 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -336,7 +336,7 @@ gfx::Rect View::GetVisibleBounds() const {
     const View* ancestor = view->parent_;
     if (ancestor != NULL) {
       ancestor_bounds.SetRect(0, 0, ancestor->width(), ancestor->height());
-      vis_bounds = vis_bounds.Intersect(ancestor_bounds);
+      vis_bounds.Intersect(ancestor_bounds);
     } else if (!view->GetWidget()) {
       // If the view has no Widget, we're not visible. Return an empty rect.
       return gfx::Rect();