Make LogoutButtonTray a regular View

ash/system/palette/palette_tray.cc

Index: ash/system/palette/palette_tray.cc
diff --git a/ash/system/palette/palette_tray.cc b/ash/system/palette/palette_tray.cc
index 98323e0c714f16fb49ae40a7ef4f8162ad7f708d..f6c46f8ca65698b80e9b07bc98aae4e304d35503 100644
--- a/ash/system/palette/palette_tray.cc
+++ b/ash/system/palette/palette_tray.cc
@@ -21,6 +21,7 @@
 #include "ash/system/tray/system_tray_delegate.h"
 #include "ash/system/tray/tray_bubble_wrapper.h"
 #include "ash/system/tray/tray_constants.h"
+#include "ash/system/tray/tray_container.h"
 #include "ash/system/tray/tray_popup_header_button.h"
 #include "ash/system/tray/tray_popup_item_style.h"
 #include "ash/wm_window.h"
@@ -128,7 +129,7 @@ class TitleView : public views::View, public views::ButtonListener {
 }  // namespace
 
 PaletteTray::PaletteTray(WmShelf* wm_shelf)
-    : TrayBackgroundView(wm_shelf, true),
+    : TrayBackgroundView(wm_shelf),
       palette_tool_manager_(new PaletteToolManager(this)),
       scoped_session_observer_(this),
       weak_factory_(this) {
@@ -362,13 +363,6 @@ WmWindow* PaletteTray::GetWindow() {
   return shelf()->GetWindow();
 }
 
-void PaletteTray::SetShelfAlignment(ShelfAlignment alignment) {
-  if (alignment == shelf_alignment())
-    return;
-
-  TrayBackgroundView::SetShelfAlignment(alignment);
-}
-
 void PaletteTray::AnchorUpdated() {
   if (bubble_)
     bubble_->bubble_view()->UpdateBubble();