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:
+  // TODO(kylechar): Replace with something like ash::DisplayInfo after it's

[rjkroege, 2016/08/30 18:41:59]

fyi: is in the commit queue

You need to say what a DisplayInfo is.

[kylechar, 2016/08/31 15:58:01]

I've updated the comment. I see display::ManagedDisplayInfo exists now but I
guess that's not totally usable yet without the rest of the display management
code.

+  // moved to src/ui/display.
+  struct DisplayInfo {
+    DisplayInfo(int64_t new_id, gfx::Rect new_bounds)
+        : id(new_id), bounds(new_bounds), known_bounds(new_bounds) {}
+
+    int64_t id;
+    // The display bounds.
+    gfx::Rect bounds;
+    // The display bounds that the delegate knows about.
+    gfx::Rect known_bounds;
+    bool removed = false;
+  };
+
   PlatformScreenImplOzone();
   ~PlatformScreenImplOzone() override;
 
- private:
   // PlatformScreen:
   void Init(PlatformScreenDelegate* delegate) override;
   int64_t GetPrimaryDisplayId() const override;
 
+ private:
+  // Process display snapshots and mark removed displays as removed. Does not
+  // call delegate.
+  void ProcessRemovedDisplays(
+      const ui::DisplayConfigurator::DisplayStateList& snapshots);
+
+  // Processes display snapshots and updates the bounds of an existing displays.
+  // Does not call delegate.
+  void ProcessModifiedDisplays(
+      const ui::DisplayConfigurator::DisplayStateList& snapshots);
+
+  // Examines list of cached displays and checks for modified or removed
+  // displays. Also updates display bounds in response to modified or removed
+  // displays. Calls OnDisplayModified() or OnDisplayRemoved() on the delegate
+  // when appropriate, at most once per display.
+  //
+  // Usually used after ProcessRemovedDisplays() and ProcessModifiedDisplays().
+  void UpdateCachedDisplays();
+
+  // Adds any new displays in the list of cached displays and calls delegate.
+  void AddNewDisplays(
+      const ui::DisplayConfigurator::DisplayStateList& snapshots);
+
   // 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_