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

ash/system/tray/special_popup_row.cc

Index: ash/system/tray/special_popup_row.cc
diff --git a/ash/system/tray/special_popup_row.cc b/ash/system/tray/special_popup_row.cc
index 0f6899d38f2ed1f3417abc44332855b45356e01d..c7a0a14d1c16ba796c23973550268f9dafecf386 100644
--- a/ash/system/tray/special_popup_row.cc
+++ b/ash/system/tray/special_popup_row.cc
@@ -96,13 +96,13 @@ void SpecialPopupRow::AddThrobber(ThrobberView* throbber) {
   button_container_->AddChildView(throbber);
 }
 
-gfx::Size SpecialPopupRow::GetPreferredSize() {
+gfx::Size SpecialPopupRow::GetPreferredSize() const {
   gfx::Size size = views::View::GetPreferredSize();
   size.set_height(kSpecialPopupRowHeight);
   return size;
 }
 
-int SpecialPopupRow::GetHeightForWidth(int width) {
+int SpecialPopupRow::GetHeightForWidth(int width) const {
   return kSpecialPopupRowHeight;
 }