Fix use after free for cached_displays_.

ui/ozone/demo/ozone_demo.cc

 // Copyright 2014 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.
 
 #include <utility>
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 73 matching lines @@
 
   void AddWindow(DemoWindow* window);
   void RemoveWindow(DemoWindow* window);
 
  private:
   void OnDisplaysAquired(const std::vector<ui::DisplaySnapshot*>& displays);
   void OnDisplayConfigured(const gfx::Rect& bounds, bool success);
 
   // ui::NativeDisplayDelegate:
   void OnConfigurationChanged() override;
+  void OnDisplaySnapshotsInvalidated() override;
 
   std::unique_ptr<ui::NativeDisplayDelegate> delegate_;
   base::Closure quit_closure_;
   RendererFactory renderer_factory_;
   std::vector<std::unique_ptr<DemoWindow>> windows_;
 
   // Flags used to keep track of the current state of display configuration.
   //
   // True if configuring the displays. In this case a new display configuration
   // isn't started.
@@ skipping 171 matching lines @@
     should_configure_ = true;
     return;
   }
 
   is_configuring_ = true;
   delegate_->GrabServer();
   delegate_->GetDisplays(
       base::Bind(&WindowManager::OnDisplaysAquired, base::Unretained(this)));
 }
 
+void WindowManager::OnDisplaySnapshotsInvalidated() {}
+
 void WindowManager::OnDisplaysAquired(
     const std::vector<ui::DisplaySnapshot*>& displays) {
   windows_.clear();
 
   gfx::Point origin;
   for (auto display : displays) {
     if (!display->native_mode()) {
       LOG(ERROR) << "Display " << display->display_id()
                  << " doesn't have a native mode";
       continue;
@@ skipping 44 matching lines @@
       ->SetCurrentLayoutByName("us");
 
   base::RunLoop run_loop;
 
   WindowManager window_manager(run_loop.QuitClosure());
 
   run_loop.Run();
 
   return 0;
 }