Process DisplaySnapshots in PlatformScreen.

services/ui/display/platform_screen_impl_ozone.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 SERVICES_UI_DISPLAY_PLATFORM_SCREEN_IMPL_OZONE_H_
 #define SERVICES_UI_DISPLAY_PLATFORM_SCREEN_IMPL_OZONE_H_
 
 #include <stdint.h>
 
 #include <set>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "services/ui/display/platform_screen.h"
 #include "ui/display/chromeos/display_configurator.h"
 #include "ui/display/display.h"
 
 namespace display {
 
 // PlatformScreenImplOzone provides the necessary functionality to configure all
 // attached physical displays on the ozone platform.
 class PlatformScreenImplOzone : public PlatformScreen,
                                 public ui::DisplayConfigurator::Observer {
  public:
   PlatformScreenImplOzone();
   ~PlatformScreenImplOzone() override;
 
- private:
   // PlatformScreen:
   void Init(PlatformScreenDelegate* delegate) override;
   int64_t GetPrimaryDisplayId() const override;
 
+ private:
+  // TODO(kylechar): This struct is just temporary until we migrate
+  // DisplayManager code out of ash so it can be used here.
+  struct DisplayInfo {
+    DisplayInfo(int64_t new_id, const gfx::Rect& new_bounds)
+        : id(new_id), bounds(new_bounds) {}
+
+    int64_t id;
+    // The display bounds.
+    gfx::Rect bounds;
+    bool modified = false;

[sky, 2016/09/02 18:29:28]

Add a description as to what this means and intended uses.

[kylechar, 2016/09/06 15:35:55]

Done.

+    bool removed = false;
+  };
+  using CachedDisplayIterator = std::vector<DisplayInfo>::iterator;
+
+  // Processes list of display snapshots and sets |removed| on any displays that
+  // have been removed. Updates |primary_display_id_| if the primary display was
+  // removed. Does not remove displays from |cached_displays_| or send updates
+  // to delegate.
+  void ProcessRemovedDisplays(
+      const ui::DisplayConfigurator::DisplayStateList& snapshots);
+
+  // Processes list of display snapshots and updates the bounds of any displays
+  // in |cached_displays_| that have changed size. Does not send updates to
+  // delegate.
+  void ProcessModifiedDisplays(
+      const ui::DisplayConfigurator::DisplayStateList& snapshots);
+
+  // Looks at |cached_displays_| for modified or removed displays. Also updates
+  // display bounds in response to modified or removed displays. Sends updates
+  // to the delegate when appropriate by calling OnDisplayModified() or
+  // OnDisplayRemoved(). Makes at most one function call per display.
+  //
+  // Usually used after ProcessRemovedDisplays() and ProcessModifiedDisplays().
+  void UpdateCachedDisplays();
+
+  // Processes list of display snapshots and adds any new displays to
+  // |cached_displays_|. Updates delegate by calling OnDisplayAdded().
+  void AddNewDisplays(
+      const ui::DisplayConfigurator::DisplayStateList& snapshots);
+
+  // Returns an iterator to the cached display with |display_id| or an end
+  // iterator if there is no display with that id.
+  CachedDisplayIterator GetCachedDisplayIterator(int64_t display_id);
+
   // ui::DisplayConfigurator::Observer:
   void OnDisplayModeChanged(
       const ui::DisplayConfigurator::DisplayStateList& displays) override;
   void OnDisplayModeChangeFailed(
       const ui::DisplayConfigurator::DisplayStateList& displays,
       ui::MultipleDisplayState failed_new_state) override;
 
   PlatformScreenDelegate* delegate_ = nullptr;
   ui::DisplayConfigurator display_configurator_;
 
   // TODO(kylechar): These values can/should be replaced by DisplayLayout.
   int64_t primary_display_id_ = display::Display::kInvalidDisplayID;
-  std::set<uint64_t> displays_;
+  std::vector<DisplayInfo> cached_displays_;
   gfx::Point next_display_origin_;
 
   DISALLOW_COPY_AND_ASSIGN(PlatformScreenImplOzone);
 };
 
 }  // namespace display
 
 #endif  // SERVICES_UI_DISPLAY_PLATFORM_SCREEN_IMPL_OZONE_H_