tweak the focus rectangle of TrayBackgroundView objects

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 0e871965e2843dbd5e9c3f1228f91e6212d9e58c..8692abafa88522f5ee648609bb52f45998ee2ac0 100644
--- a/ash/common/system/tray/tray_background_view.cc
+++ b/ash/common/system/tray/tray_background_view.cc
@@ -6,6 +6,7 @@
 
 #include <algorithm>
 
+#include "ash/common/ash_constants.h"
 #include "ash/common/material_design/material_design_controller.h"
 #include "ash/common/shelf/shelf_constants.h"
 #include "ash/common/shelf/wm_shelf.h"
@@ -567,6 +568,12 @@ gfx::Rect TrayBackgroundView::GetFocusBounds() {
   return GetContentsBounds();
 }
 
+void TrayBackgroundView::OnPaintFocus(gfx::Canvas* canvas) {
+  gfx::Rect paint_bounds(GetFocusBounds());
+  paint_bounds.Inset(2, -2, 3, -2);
+  canvas->DrawSolidFocusRect(paint_bounds, kFocusBorderColor);
+}
+
 void TrayBackgroundView::OnPaint(gfx::Canvas* canvas) {
   ActionableView::OnPaint(canvas);
   if (!MaterialDesignController::IsShelfMaterial() ||