Changes threshold frequency for investigation (based on video in the bug)

ash/common/shelf/wm_shelf.h

 // Copyright 2016 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.
 
 #ifndef ASH_COMMON_SHELF_WM_SHELF_H_
 #define ASH_COMMON_SHELF_WM_SHELF_H_
 
 #include <memory>
 
 #include "ash/ash_export.h"
 #include "ash/common/shelf/shelf_layout_manager_observer.h"
 #include "ash/public/cpp/shelf_types.h"
 #include "base/observer_list.h"
 #include "base/time/time.h"
 
 namespace gfx {
 class Rect;
 }
 
 namespace ui {
 class GestureEvent;
 }
 
 namespace ash {
 
 class ShelfLayoutManager;
+class ShelfLayoutManagerTest;
 class ShelfLockingManager;
 class ShelfView;
 class ShelfWidget;
 class StatusAreaWidget;
 class WmShelfObserver;
 class WmWindow;
 
 // Controller for the shelf state. Exists for the lifetime of each root window
 // controller. Note that the shelf widget may not be created until after login.
 class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
@@ skipping 102 matching lines @@
   ~WmShelf() override;
 
   // ShelfLayoutManagerObserver:
   void WillDeleteShelfLayoutManager() override;
   void WillChangeVisibilityState(ShelfVisibilityState new_state) override;
   void OnAutoHideStateChanged(ShelfAutoHideState new_state) override;
   void OnBackgroundUpdated(ShelfBackgroundType background_type,
                            BackgroundAnimatorChangeType change_type) override;
 
  private:
+  friend class ShelfLayoutManagerTest;
+
   // Layout manager for the shelf container window. Instances are constructed by
   // ShelfWidget and lifetimes are managed by the container windows themselves.
   ShelfLayoutManager* shelf_layout_manager_ = nullptr;
 
   std::unique_ptr<ShelfWidget> shelf_widget_;
 
   // Internal implementation detail. Do not expose externally. Owned by views
   // hierarchy. Null before login and in secondary display init.
   ShelfView* shelf_view_ = nullptr;
 
   ShelfAlignment alignment_ = SHELF_ALIGNMENT_BOTTOM_LOCKED;
 
   // Sets shelf alignment to bottom during login and screen lock.
   std::unique_ptr<ShelfLockingManager> shelf_locking_manager_;
 
   ShelfAutoHideBehavior auto_hide_behavior_ = SHELF_AUTO_HIDE_BEHAVIOR_NEVER;
 
   base::ObserverList<WmShelfObserver> observers_;
 
   // Temporary. Used to investigate http://crbug.com/665093 .
   base::TimeTicks time_last_auto_hide_change_;
   int count_auto_hide_changes_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(WmShelf);
 };
 
 }  // namespace ash
 
 #endif  // ASH_COMMON_SHELF_WM_SHELF_H_