chromeos: Rename ash::WmShelf to Shelf

ash/metrics/user_metrics_recorder.cc

Index: ash/metrics/user_metrics_recorder.cc
diff --git a/ash/metrics/user_metrics_recorder.cc b/ash/metrics/user_metrics_recorder.cc
index fb6a630b27adfa4099d0b101472591af42bca8db..aa04f364d6136b56be350e9260a72d73b547b307 100644
--- a/ash/metrics/user_metrics_recorder.cc
+++ b/ash/metrics/user_metrics_recorder.cc
@@ -10,9 +10,9 @@
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/session/session_controller.h"
 #include "ash/session/session_state_delegate.h"
+#include "ash/shelf/shelf.h"
 #include "ash/shelf/shelf_model.h"
 #include "ash/shelf/shelf_view.h"
-#include "ash/shelf/wm_shelf.h"
 #include "ash/shell.h"
 #include "ash/wm/window_state.h"
 #include "ash/wm_window.h"
@@ -624,7 +624,7 @@ void UserMetricsRecorder::OnShellShuttingDown() {
 }
 
 void UserMetricsRecorder::RecordPeriodicMetrics() {
-  WmShelf* shelf = WmShelf::ForWindow(Shell::GetPrimaryRootWindow());
+  Shelf* shelf = Shelf::ForWindow(Shell::GetPrimaryRootWindow());
   // TODO(bruthig): Investigating whether the check for |manager| is necessary
   // and add tests if it is.
   if (shelf) {