Refactor most recently used window tracking into a separate class.

ash/shelf/shelf_layout_manager.cc

Index: ash/shelf/shelf_layout_manager.cc
diff --git a/ash/shelf/shelf_layout_manager.cc b/ash/shelf/shelf_layout_manager.cc
index e0d06d71ae1c2e3caabfd5bfb9b1c46b6c9ad69f..0745fe5d834f0761d60710f884107f488f2b701c 100644
--- a/ash/shelf/shelf_layout_manager.cc
+++ b/ash/shelf/shelf_layout_manager.cc
@@ -23,8 +23,8 @@
 #include "ash/shell_window_ids.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/wm/gestures/shelf_gesture_handler.h"
+#include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/property_util.h"
-#include "ash/wm/window_cycle_controller.h"
 #include "ash/wm/window_properties.h"
 #include "ash/wm/window_util.h"
 #include "ash/wm/workspace/workspace_animations.h"
@@ -937,7 +937,7 @@ ShelfAutoHideState ShelfLayoutManager::CalculateAutoHideState(
     return SHELF_AUTO_HIDE_SHOWN;
 
   const std::vector<aura::Window*> windows =
-      ash::WindowCycleController::BuildWindowList(NULL, false);
+      ash::MruWindowTracker::BuildWindowList(NULL, false);
 
   // Process the window list and check if there are any visible windows.
   for (size_t i = 0; i < windows.size(); ++i) {