ash: Show better focus rects for the tray.

ash/system/user/tray_user.cc

Index: ash/system/user/tray_user.cc
diff --git a/ash/system/user/tray_user.cc b/ash/system/user/tray_user.cc
index d846cbf0334ea039d4015597e4f54c3a82714c9b..c47aa4ca8e833c25d4b3a2176349bda8f162bb9c 100644
--- a/ash/system/user/tray_user.cc
+++ b/ash/system/user/tray_user.cc
@@ -87,6 +87,13 @@ class TrayButton : public views::TextButton {
       views::TextButton::OnPaintBorder(canvas);
   }
 
+  void OnPaintFocusBorder(gfx::Canvas* canvas) OVERRIDE {
+    if (HasFocus() && (focusable() || IsAccessibilityFocusable())) {
+      canvas->DrawRect(gfx::Rect(1, 1, width() - 3, height() - 3),
+                       ash::kFocusBorderColor);
+    }
+  }
+
   bool hover_;
   scoped_ptr<views::Background> hover_bg_;
   scoped_ptr<views::Border> hover_border_;