Remove the extra separator appears on the right side of the shelf

ash/common/system/tray/tray_background_view.cc

Index: ash/common/system/tray/tray_background_view.cc
diff --git a/ash/common/system/tray/tray_background_view.cc b/ash/common/system/tray/tray_background_view.cc
index 3da2d1b35243478513dce07313447ed283c80ac6..ca31e2acd8e358e286cb1bd5af5372ba6df0b7f5 100644
--- a/ash/common/system/tray/tray_background_view.cc
+++ b/ash/common/system/tray/tray_background_view.cc
@@ -291,6 +291,7 @@ TrayBackgroundView::TrayBackgroundView(WmShelf* wm_shelf)
       shelf_alignment_(SHELF_ALIGNMENT_BOTTOM),
       background_(NULL),
       is_active_(false),
+      is_separator_visible_(true),
       widget_observer_(new TrayWidgetObserver(this)) {
   DCHECK(wm_shelf_);
   set_notify_enter_exit_on_child(true);
@@ -520,6 +521,13 @@ void TrayBackgroundView::UpdateShelfItemBackground(int alpha) {
   }
 }
 
+void TrayBackgroundView::SetSeparatorVisibility(bool is_shown) {

[James Cook, 2017/01/09 23:50:53]

nit: whatever you choose in the header, make sure this matches the header

[yiyix, 2017/01/10 01:02:53]

Done.

+  if (is_separator_visible_ == is_shown)
+    return;
+  is_separator_visible_ = is_shown;
+  SchedulePaint();

[James Cook, 2017/01/09 23:50:53]

Is this needed? The two places you call SetSeparatorVisibility() are in
constructors, so it doesn't seem to me like you would need to schedule a paint.

If you don't need this then the function could be set_separator_visible() in the
header (or similar).

[yiyix, 2017/01/10 01:02:53]

I don't need SchedulePaint() now. I was thinking how separator_visible setting
can be used in the future. I think i have complicated the problem.

+}
+
 views::View* TrayBackgroundView::GetBubbleAnchor() const {
   return tray_container_;
 }
@@ -581,7 +589,8 @@ void TrayBackgroundView::OnPaint(gfx::Canvas* canvas) {
   ActionableView::OnPaint(canvas);
   if (!MaterialDesignController::IsShelfMaterial() ||
       shelf()->GetBackgroundType() ==
-          ShelfBackgroundType::SHELF_BACKGROUND_DEFAULT) {
+          ShelfBackgroundType::SHELF_BACKGROUND_DEFAULT ||
+      !is_separator_visible_) {
     return;
   }
   //  In the given |canvas|, for a horizontal shelf draw a separator line to the