Handle modified displays in mustash.

ui/display/display_list.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 UI_DISPLAY_DISPLAY_LIST_H_
 #define UI_DISPLAY_DISPLAY_LIST_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 47 matching lines @@
   Displays::const_iterator FindDisplayById(int64_t id) const;
   Displays::iterator FindDisplayById(int64_t id);
 
   Displays::const_iterator GetPrimaryDisplayIterator() const;
 
   // Internally increments a counter that while non-zero results in observers
   // not being called for any changes to the displays. It is assumed once
   // callers release the last lock they call the observers appropriately.
   std::unique_ptr<DisplayListObserverLock> SuspendObserverUpdates();
 
-  // Updates the cached id based on display.id() as well as whether the Display
-  // is the primary display.
+  // Updates the cached display based on display.id().
+  void UpdateDisplay(const display::Display& display);
+
+  // Updates the cached display based on display.id(). Also updates the primary
+  // display if |type| indicates |display| is the primary display.
   void UpdateDisplay(const display::Display& display, Type type);
 
   // Adds a new Display.
   void AddDisplay(const display::Display& display, Type type);
 
   // Removes the Display with the specified id.
   void RemoveDisplay(int64_t id);
 
   base::ObserverList<display::DisplayObserver>* observers() {
     return &observers_;
   }
 
  private:
   friend class DisplayListObserverLock;
 
   bool should_notify_observers() const {
     return observer_suspend_lock_count_ == 0;
   }
   void IncrementObserverSuspendLockCount();
   void DecrementObserverSuspendLockCount();
 
+  Type GetTypeByDisplayId(int64_t display_id) const;
+
   std::vector<display::Display> displays_;
   int primary_display_index_ = -1;
   base::ObserverList<display::DisplayObserver> observers_;
 
   int observer_suspend_lock_count_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayList);
 };
 
 }  // namespace display
 
 #endif  // UI_DISPLAY_DISPLAY_LIST_H_