Detect and fix overlapping displays

ui/display/manager/display_manager.h

 // 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.
 
 #ifndef UI_DISPLAY_MANAGER_DISPLAY_MANAGER_H_
 #define UI_DISPLAY_MANAGER_DISPLAY_MANAGER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 106 matching lines @@
 
   // Initialize default display.
   void InitDefaultDisplay();
 
   // Initializes font related params that depends on display configuration.
   void RefreshFontParams();
 
   // Returns the display layout used for current displays.
   const DisplayLayout& GetCurrentDisplayLayout() const;
 
+  // Returns the actual display layout after it has been resolved and applied.
+  const DisplayLayout& GetCurrentResolvedDisplayLayout() const;
+
   // Returns the current display list.
   DisplayIdList GetCurrentDisplayIdList() const;
 
   // Sets the layout for the current display pair. The |layout| specifies the
   // locaion of the displays relative to their parents.
   void SetLayoutForCurrentDisplays(std::unique_ptr<DisplayLayout> layout);
 
   // Returns display for given |id|;
   const Display& GetDisplayForId(int64_t id) const;
 
@@ skipping 264 matching lines @@
   void UpdateNonPrimaryDisplayBoundsForLayout(
       Displays* display_list,
       std::vector<size_t>* updated_indices);
 
   void CreateMirrorWindowIfAny();
 
   void RunPendingTasksForTest();
 
   // Applies the |layout| and updates the bounds of displays in |display_list|.
   // |updated_ids| contains the ids for displays whose bounds have changed.
-  void ApplyDisplayLayout(const DisplayLayout& layout,
+  void ApplyDisplayLayout(DisplayLayout* layout,
                           Displays* display_list,
                           std::vector<int64_t>* updated_ids);
 
   Delegate* delegate_ = nullptr;  // not owned.
 
   std::unique_ptr<Screen> screen_;
 
   std::unique_ptr<DisplayLayoutStore> layout_store_;
 
+  std::unique_ptr<DisplayLayout> current_resolved_layout_;
+
   int64_t first_display_id_ = kInvalidDisplayId;
 
   // List of current active displays.
   Displays active_display_list_;
   // This list does not include the displays that will be removed if
   // |UpdateDisplaysWith| is under execution.
   // See https://crbug.com/632755
   Displays active_only_display_list_;
 
   // True if active_display_list is being modified and has displays that are not
@@ skipping 34 matching lines @@
   base::ObserverList<DisplayObserver> observers_;
 
   base::WeakPtrFactory<DisplayManager> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DisplayManager);
 };
 
 }  // namespace display
 
 #endif  // UI_DISPLAY_MANAGER_DISPLAY_MANAGER_H_