Implement all system menu title row buttons for Ash MD

ash/common/system/tray/tray_utils.cc

Index: ash/common/system/tray/tray_utils.cc
diff --git a/ash/common/system/tray/tray_utils.cc b/ash/common/system/tray/tray_utils.cc
index d7c9dd21669267c0b4ceb8774f2994b59b070847..74b525881833703ce40588bd5c5ecbc9868a1617 100644
--- a/ash/common/system/tray/tray_utils.cc
+++ b/ash/common/system/tray/tray_utils.cc
@@ -5,9 +5,11 @@
 #include "ash/common/system/tray/tray_utils.h"
 
 #include "ash/common/material_design/material_design_controller.h"
+#include "ash/common/session/session_state_delegate.h"
 #include "ash/common/shelf/wm_shelf_util.h"
 #include "ash/common/system/tray/tray_constants.h"
 #include "ash/common/system/tray/tray_item_view.h"
+#include "ash/common/wm_shell.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/gfx/font_list.h"
 #include "ui/gfx/geometry/vector2d.h"
@@ -86,4 +88,10 @@ void GetAccessibleLabelFromDescendantViews(
     GetAccessibleLabelFromDescendantViews(view->child_at(i), out_labels);
 }
 
+bool CanOpenWebUISettings(LoginStatus status) {

[bruthig, 2016/10/19 15:43:09]

It seems kind of odd that we query the TrayUtils to determine if the settings
can be shown but then ask specific delegates owned by the WmShell to actually
show the settings.  I think it would make more sense to ask each of these
delegates (or the WmShell), "CanShowSettings()" and if true, then
"ShowSettings()".

[tdanderson, 2016/10/19 19:49:31]

Added a corresponding TODO.

[bruthig, 2016/10/19 20:17:58]

Acknowledged.

+  return status != LoginStatus::NOT_LOGGED_IN &&
+         status != LoginStatus::LOCKED &&
+         !WmShell::Get()->GetSessionStateDelegate()->IsInSecondaryLoginScreen();
+}
+
 }  // namespace ash