Process DisplaySnapshots in PlatformScreen.

services/ui/display/platform_screen_impl_ozone.h

Index: services/ui/display/platform_screen_impl_ozone.h
diff --git a/services/ui/display/platform_screen_impl_ozone.h b/services/ui/display/platform_screen_impl_ozone.h
index d7282df3bcce91440d9d324d84057ffe994bd51d..c9defb75220e70c6016f4163b04e5dc39ceae19e 100644
--- a/services/ui/display/platform_screen_impl_ozone.h
+++ b/services/ui/display/platform_screen_impl_ozone.h
@@ -23,14 +23,50 @@ namespace display {
 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;
@@ -43,7 +79,7 @@ class PlatformScreenImplOzone : public PlatformScreen,
 
   // 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);