Converts MruWindowTracker to work with common types

ash/shell.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/shell.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
@@ skipping 1030 matching lines @@
   mouse_cursor_filter_.reset(new MouseCursorEventFilter());
   PrependPreTargetHandler(mouse_cursor_filter_.get());
 
   // Create Controllers that may need root window.
   // TODO(oshima): Move as many controllers before creating
   // RootWindowController as possible.
   visibility_controller_.reset(new AshVisibilityController);
 
   magnification_controller_.reset(
       MagnificationController::CreateInstance());
-  mru_window_tracker_.reset(new MruWindowTracker(activation_client_,
-                                                 focus_rules));
+  mru_window_tracker_.reset(new MruWindowTracker);
 
   partial_magnification_controller_.reset(
       new PartialMagnificationController());
 
   autoclick_controller_.reset(AutoclickController::CreateInstance());
 
   high_contrast_controller_.reset(new HighContrastController);
   video_detector_.reset(new VideoDetector);
   window_selector_controller_.reset(new WindowSelectorController());
   window_cycle_controller_.reset(new WindowCycleController());
@@ skipping 186 matching lines @@
 
 void Shell::OnWindowActivated(
     aura::client::ActivationChangeObserver::ActivationReason reason,
     aura::Window* gained_active,
     aura::Window* lost_active) {
   if (gained_active)
     target_root_window_ = gained_active->GetRootWindow();
 }
 
 }  // namespace ash