Update shelf spacing in Chrome OS according to the MD specs

ash/system/status_area_widget_delegate.h

Index: ash/system/status_area_widget_delegate.h
diff --git a/ash/system/status_area_widget_delegate.h b/ash/system/status_area_widget_delegate.h
index 4dfa668787e1eede699f656389d455502461aeb9..7ecf7980640477d29541104bbde16f2617212731 100644
--- a/ash/system/status_area_widget_delegate.h
+++ b/ash/system/status_area_widget_delegate.h
@@ -14,6 +14,10 @@
 #include "ui/views/widget/widget_delegate.h"
 
 namespace ash {

[tdanderson, 2016/06/10 22:54:43]

you don't need/want both line 16 and line 20

[yiyix, 2016/06/13 18:43:55]

Done.

+class TrayBackgroundView;
+}
+
+namespace ash {
 class FocusCycler;
 
 class ASH_EXPORT StatusAreaWidgetDelegate : public views::AccessiblePaneView,
@@ -23,7 +27,7 @@ class ASH_EXPORT StatusAreaWidgetDelegate : public views::AccessiblePaneView,
   ~StatusAreaWidgetDelegate() override;
 
   // Add a tray view to the widget (e.g. system tray, web notifications).
-  void AddTray(views::View* tray);
+  void AddTray(TrayBackgroundView* tray);

[tdanderson, 2016/06/10 22:54:43]

I was looking over the chat you, me, and Ben had last week (in the CL comments)
and he suggested using a static_cast<TrayBackgroundView> in
StatusAreaWidgetDelegate::UpdateLayout(). You haven't done that, but I think I
actually prefer what you've done instead (move the border-setting code out of
TrayBackgroundView and into StatusAreaWidgetDelegate).

So with that said, since you're not doing the static cast, there's really no
reason to change this type anymore. I'd just keep it as a View*. (Also you can
remove the class declaration on line 17)

[yiyix, 2016/06/13 18:43:55]

I did not really like the casting. I am glad that you prefer this way as well.

 
   // Called whenever layout might change (e.g. alignment changed).
   void UpdateLayout();
@@ -55,6 +59,11 @@ class ASH_EXPORT StatusAreaWidgetDelegate : public views::AccessiblePaneView,
  private:
   void UpdateWidgetSize();
 
+  // Tray shows on the right most edge requires an extra wide inset, so edge is

[tdanderson, 2016/06/10 22:54:43]

nit on wording, change to something like: "Sets a border on |child|. If
|extend_border_to_edge| is true, then an extra wide border is added to extend
the view's hit region to the edge of the screen."

[yiyix, 2016/06/13 18:43:55]

Done.

+  // included the hitting area .
+  void SetBorderOnEdgeTray(views::View* child);
+  void SetBorderOnNonEdgeTray(views::View* child);

[tdanderson, 2016/06/10 22:54:43]

Combine into a single function, such as:

void SetBorderOnChild(View* child, bool extend_border_to_edge)

[yiyix, 2016/06/13 18:43:55]

Done.

+
   const FocusCycler* focus_cycler_for_testing_;
   ShelfAlignment alignment_;