[ash/shelf] ResourceBundle should be used as pointer not non-const ref

ash/shelf/shelf_widget.cc

Index: ash/shelf/shelf_widget.cc
diff --git a/ash/shelf/shelf_widget.cc b/ash/shelf/shelf_widget.cc
index 96e75ce478ab819ff8c7b95e119871cf20770067..95bc68942fe037c6299fadd5de03a2f1e22a551c 100644
--- a/ash/shelf/shelf_widget.cc
+++ b/ash/shelf/shelf_widget.cc
@@ -172,9 +172,9 @@ void DimmerView::ForceUndimming(bool force) {
 
 void DimmerView::OnPaintBackground(gfx::Canvas* canvas) {
   SkPaint paint;
-  ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
+  ui::ResourceBundle* rb = &ui::ResourceBundle::GetSharedInstance();
   gfx::ImageSkia shelf_background =
-      *rb.GetImageNamed(IDR_ASH_SHELF_DIMMING).ToImageSkia();
+      *rb->GetImageNamed(IDR_ASH_SHELF_DIMMING).ToImageSkia();
 
   if (shelf_->GetAlignment() != ash::SHELF_ALIGNMENT_BOTTOM) {
     shelf_background = gfx::ImageSkiaOperations::CreateRotatedImage(
@@ -463,9 +463,9 @@ void ShelfWidget::DelegateView::SetParentLayer(ui::Layer* layer) {
 }
 
 void ShelfWidget::DelegateView::OnPaintBackground(gfx::Canvas* canvas) {
-  ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
+  ui::ResourceBundle* rb = &ui::ResourceBundle::GetSharedInstance();
   gfx::ImageSkia shelf_background =
-      *rb.GetImageSkiaNamed(IDR_ASH_SHELF_BACKGROUND);
+      *rb->GetImageSkiaNamed(IDR_ASH_SHELF_BACKGROUND);
   if (SHELF_ALIGNMENT_BOTTOM != shelf_->GetAlignment())
     shelf_background = gfx::ImageSkiaOperations::CreateRotatedImage(
         shelf_background,
@@ -498,7 +498,7 @@ void ShelfWidget::DelegateView::OnPaintBackground(gfx::Canvas* canvas) {
     // The part of the shelf background that is in the corner below the docked
     // windows close to the work area is an arched gradient that blends
     // vertically oriented docked background and horizontal shelf.
-    gfx::ImageSkia shelf_corner = *rb.GetImageSkiaNamed(IDR_ASH_SHELF_CORNER);
+    gfx::ImageSkia shelf_corner = *rb->GetImageSkiaNamed(IDR_ASH_SHELF_CORNER);
     if (dock_bounds.x() == 0) {
       shelf_corner = gfx::ImageSkiaOperations::CreateRotatedImage(
           shelf_corner, SkBitmapOperations::ROTATION_90_CW);