[Chrome OS MD] Draw a 1px separator between 2 tray items

ash/common/system/tray/tray_background_view.h

Index: ash/common/system/tray/tray_background_view.h
diff --git a/ash/common/system/tray/tray_background_view.h b/ash/common/system/tray/tray_background_view.h
index 478e427bda77e0b79719747d9decd52ee0a0e6a2..23255aca015ded5d9322b57f1173b6e2c342ed47 100644
--- a/ash/common/system/tray/tray_background_view.h
+++ b/ash/common/system/tray/tray_background_view.h
@@ -19,12 +19,13 @@ namespace ash {
 class ShelfLayoutManager;
 class TrayEventFilter;
 class TrayBackground;
+class ViewObserver;
 class WmShelf;
 
 // Base class for children of StatusAreaWidget: SystemTray, WebNotificationTray,
 // LogoutButtonTray, OverviewButtonTray.
 // This class handles setting and animating the background when the Launcher
-// his shown/hidden. It also inherits from ActionableView so that the tray
+// is shown/hidden. It also inherits from ActionableView so that the tray
 // items can override PerformAction when clicked on.
 class ASH_EXPORT TrayBackgroundView : public ActionableView,
                                       public BackgroundAnimatorDelegate,
@@ -62,7 +63,10 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
     DISALLOW_COPY_AND_ASSIGN(TrayContainer);
   };
 
-  explicit TrayBackgroundView(WmShelf* wm_shelf);
+  // Creates a TrayBackgroundView and adds a |view_observer| to observe when
+  // this tray visibility changes, so that the separator visibility can be
+  // updated accordingly.
+  explicit TrayBackgroundView(WmShelf* wm_shelf, ViewObserver* view_observer);
   ~TrayBackgroundView() override;
 
   // Called after the tray has been added to the widget containing it.
@@ -77,6 +81,7 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   void ChildPreferredSizeChanged(views::View* child) override;
   void GetAccessibleState(ui::AXViewState* state) override;
   void AboutToRequestFocusFromTabTraversal(bool reverse) override;
+  void OnPaint(gfx::Canvas* canvas) override;
 
   // ActionableView:
   bool PerformAction(const ui::Event& event) override;
@@ -135,13 +140,17 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   // Updates the arrow visibility based on the launcher visibility.
   void UpdateBubbleViewArrow(views::TrayBubbleView* bubble_view);
 
+  // Updates the visibility of this tray's separator.
+  void SetSeparatorVisibility(bool is_show);
+
+ protected:
+  // In the given |canvas|, draws a 1px wide and 32dp tall separator line to the
+  // right of this TrayBackgeoundView item.
+  void DrawSeparator(gfx::Canvas* canvas);
+
  private:
   class TrayWidgetObserver;
 
-  // Called from Initialize after all status area trays have been created.
-  // Sets the border based on the position of the view.
-  void SetTrayBorder();
-
   // ui::ImplicitAnimationObserver:
   void OnImplicitAnimationsCompleted() override;
   bool RequiresNotificationWhenAnimatorDestroyed() const override;
@@ -150,6 +159,12 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   // SetVisible(false) is called.
   void HideTransformation();
 
+  // For Material Design, extra padding is added to tray items so there is
+  // enough places to draw separator between this tray and the tray to the left
+  // (if horizontally aligned) or to the bottom (if vertically aligned) if a
+  // separator is needed. No border is set for non-MD.
+  void CalculateAndSetTrayContainerBorder();
+
   // The shelf containing the system tray for this view.
   WmShelf* wm_shelf_;
 
@@ -167,6 +182,8 @@ class ASH_EXPORT TrayBackgroundView : public ActionableView,
   // differently if set to true.
   bool draw_background_as_active_;
 
+  ViewObserver* view_observer_;
+  bool is_separator_visible_;
   std::unique_ptr<TrayWidgetObserver> widget_observer_;
   std::unique_ptr<TrayEventFilter> tray_event_filter_;