Stop using shell::GetInstance()->system_tray() in system tray items

ash/system/tray/system_tray_bubble.cc

Index: ash/system/tray/system_tray_bubble.cc
diff --git a/ash/system/tray/system_tray_bubble.cc b/ash/system/tray/system_tray_bubble.cc
index aff271958f1d185ee9e67f755f413551037aeeb3..e567ff60939f4f6288a54ba67a985fe88557e6c4 100644
--- a/ash/system/tray/system_tray_bubble.cc
+++ b/ash/system/tray/system_tray_bubble.cc
@@ -16,7 +16,7 @@
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/canvas.h"
-#include "ui/views/layout/box_layout.h"
+#include "ui/views/layout/fill_layout.h"
 #include "ui/views/view.h"
 #include "ui/views/widget/widget.h"
 
@@ -43,10 +43,7 @@ class TrayPopupItemContainer : public views::View {
       : hover_(false),
         change_background_(change_background) {
     set_notify_enter_exit_on_child(true);
-    views::BoxLayout* layout = new views::BoxLayout(
-        views::BoxLayout::kVertical, 0, 0, 0);
-    layout->set_spread_blank_space(true);
-    SetLayoutManager(layout);
+    SetLayoutManager(new views::FillLayout);
     SetPaintToLayer(view->layer() != NULL);
     if (view->layer())
       SetFillsBoundsOpaquely(view->layer()->fills_bounds_opaquely());
@@ -317,13 +314,14 @@ bool SystemTrayBubble::ShouldShowLauncher() const {
 }
 
 void SystemTrayBubble::CreateItemViews(user::LoginStatus login_status) {
+  const int bubble_width = bubble_view_->GetPreferredSize().width();
   for (std::vector<ash::SystemTrayItem*>::iterator it = items_.begin();
        it != items_.end();
        ++it) {
     views::View* view = NULL;
     switch (bubble_type_) {
       case BUBBLE_TYPE_DEFAULT:
-        view = (*it)->CreateDefaultView(login_status);
+        view = (*it)->CreateDefaultView(login_status, bubble_width);
         break;
       case BUBBLE_TYPE_DETAILED:
         view = (*it)->CreateDetailedView(login_status);
@@ -335,6 +333,10 @@ void SystemTrayBubble::CreateItemViews(user::LoginStatus login_status) {
     if (view) {
       bubble_view_->AddChildView(new TrayPopupItemContainer(
           view, tray_->shelf_alignment(), bubble_type_ == BUBBLE_TYPE_DEFAULT));
+      if (bubble_type_ == BUBBLE_TYPE_DEFAULT &&
+          (*it)->GuaranteeDefaultViewPreferredSize(login_status)) {
+        bubble_view_->SetMinWidth(view->GetPreferredSize().width());
+      }
     }
   }
 }