Refactor most recently used window tracking into a separate class.

chrome/browser/chromeos/extensions/wallpaper_private_api.cc

Index: chrome/browser/chromeos/extensions/wallpaper_private_api.cc
diff --git a/chrome/browser/chromeos/extensions/wallpaper_private_api.cc b/chrome/browser/chromeos/extensions/wallpaper_private_api.cc
index 1d79a694f695bcb0005d25096474b92c29226861..5fc587678f14bd035184a51a73d3d2f62c37d055 100644
--- a/chrome/browser/chromeos/extensions/wallpaper_private_api.cc
+++ b/chrome/browser/chromeos/extensions/wallpaper_private_api.cc
@@ -7,7 +7,7 @@
 #include <vector>
 
 #include "ash/shell.h"
-#include "ash/wm/window_cycle_controller.h"
+#include "ash/wm/mru_window_tracker.h"
 #include "ash/wm/window_util.h"
 #include "base/file_util.h"
 #include "base/files/file_enumerator.h"
@@ -141,7 +141,7 @@ class WindowStateManager : public aura::WindowObserver {
   }
 
   void BuildWindowListAndMinimizeInactive(aura::Window* active_window) {
-    windows_ = ash::WindowCycleController::BuildWindowList(NULL, false);
+    windows_ = ash::MruWindowTracker::BuildWindowList(false);
     // Remove active window.
     std::vector<aura::Window*>::iterator last =
         std::remove(windows_.begin(), windows_.end(), active_window);