views: Make view::Views::GetPreferredSize() const.

ui/views/window/non_client_view.cc

Index: ui/views/window/non_client_view.cc
diff --git a/ui/views/window/non_client_view.cc b/ui/views/window/non_client_view.cc
index 89df367debe553fd8969f32d108cc205458c67f0..86c362a7e072d44c6e5815011b76de6da4653e3f 100644
--- a/ui/views/window/non_client_view.cc
+++ b/ui/views/window/non_client_view.cc
@@ -134,7 +134,7 @@ void NonClientView::SetAccessibleName(const base::string16& name) {
 ////////////////////////////////////////////////////////////////////////////////
 // NonClientView, View overrides:
 
-gfx::Size NonClientView::GetPreferredSize() {
+gfx::Size NonClientView::GetPreferredSize() const {
   // TODO(pkasting): This should probably be made to look similar to
   // GetMinimumSize() below.  This will require implementing GetPreferredSize()
   // better in the various frame views.
@@ -142,7 +142,7 @@ gfx::Size NonClientView::GetPreferredSize() {
   return GetWindowBoundsForClientBounds(client_bounds).size();
 }
 
-gfx::Size NonClientView::GetMinimumSize() {
+gfx::Size NonClientView::GetMinimumSize() const {
   return frame_view_->GetMinimumSize();
 }