Update shelf spacing in Chrome OS according to the MD specs

ash/system/status_area_widget_delegate.cc

Index: ash/system/status_area_widget_delegate.cc
diff --git a/ash/system/status_area_widget_delegate.cc b/ash/system/status_area_widget_delegate.cc
index 322e68dea4c9d20860b2db655afdf1a82b32a7a6..46fa5f6e5fabbf35fc99a93274e3518593a5abd8 100644
--- a/ash/system/status_area_widget_delegate.cc
+++ b/ash/system/status_area_widget_delegate.cc
@@ -121,12 +121,14 @@ void StatusAreaWidgetDelegate::UpdateLayout() {
       if (!child->visible())
         continue;
       if (!is_first_visible_child)
-        columns->AddPaddingColumn(0, kTraySpacing);
+        columns->AddPaddingColumn(0, GetShelfStatusAreaInset(TRAY_SPACING));
       is_first_visible_child = false;
       columns->AddColumn(views::GridLayout::CENTER, views::GridLayout::FILL,
                          0, /* resize percent */
                          views::GridLayout::USE_PREF, 0, 0);
     }
+    columns->AddPaddingColumn(
+        0, GetShelfStatusAreaInset(PADDING_FROM_EDGE_OF_SHELF));
     layout->StartRow(0, 0);
     for (int c = child_count() - 1; c >= 0; --c) {
       views::View* child = child_at(c);
@@ -143,11 +145,13 @@ void StatusAreaWidgetDelegate::UpdateLayout() {
       if (!child->visible())
         continue;
       if (!is_first_visible_child)
-        layout->AddPaddingRow(0, kTraySpacing);
+        layout->AddPaddingRow(0, GetShelfStatusAreaInset(TRAY_SPACING));
       is_first_visible_child = false;
       layout->StartRow(0, 0);
       layout->AddView(child);
     }
+    layout->AddPaddingRow(0,
+                          GetShelfStatusAreaInset(PADDING_FROM_EDGE_OF_SHELF));
   }
 
   layer()->GetAnimator()->StopAnimating();