Views - init less stuff in tabless browsers.

chrome/browser/ui/views/toolbar/toolbar_view.h

Index: chrome/browser/ui/views/toolbar/toolbar_view.h
diff --git a/chrome/browser/ui/views/toolbar/toolbar_view.h b/chrome/browser/ui/views/toolbar/toolbar_view.h
index c8914bd29fbd3043b76298c0f38a3a0a481fe085..f7468dd1ce93499f6c6f15dec15e540ec28720d6 100644
--- a/chrome/browser/ui/views/toolbar/toolbar_view.h
+++ b/chrome/browser/ui/views/toolbar/toolbar_view.h
@@ -202,7 +202,8 @@ class ToolbarView : public views::AccessiblePaneView,
 
   int content_shadow_height() const;
 
-  // Controls
+  // Controls. Most of these can be null, e.g. in popup windows. Only
+  // |location_bar_| is guaranteed to exist.
   BackButton* back_;
   ToolbarButton* forward_;
   ReloadButton* reload_;
@@ -210,6 +211,7 @@ class ToolbarView : public views::AccessiblePaneView,
   LocationBarView* location_bar_;
   BrowserActionsContainer* browser_actions_;
   AppMenuButton* app_menu_button_;
+
   Browser* browser_;
 
   AppMenuBadgeController badge_controller_;
@@ -218,7 +220,7 @@ class ToolbarView : public views::AccessiblePaneView,
   BooleanPrefMember show_home_button_;
 
   // The display mode used when laying out the toolbar.
-  DisplayMode display_mode_;
+  const DisplayMode display_mode_;
 
   content::NotificationRegistrar registrar_;