Fix use after free for cached_displays_.

ui/ozone/platform/drm/host/drm_native_display_delegate.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 "ui/ozone/platform/drm/host/drm_native_display_delegate.h"
 
 #include "ui/display/types/display_snapshot.h"
 #include "ui/display/types/native_display_observer.h"
 #include "ui/ozone/platform/drm/host/drm_display_host.h"
 #include "ui/ozone/platform/drm/host/drm_display_host_manager.h"
 
 namespace ui {
 
 DrmNativeDisplayDelegate::DrmNativeDisplayDelegate(
     DrmDisplayHostManager* display_manager)
     : display_manager_(display_manager) {
 }
 
 DrmNativeDisplayDelegate::~DrmNativeDisplayDelegate() {
   display_manager_->RemoveDelegate(this);
 }
 
 void DrmNativeDisplayDelegate::OnConfigurationChanged() {
   for (NativeDisplayObserver& observer : observers_)
     observer.OnConfigurationChanged();
 }
 
+void DrmNativeDisplayDelegate::OnDisplaySnapshotsInvalidated() {
+  for (NativeDisplayObserver& observer : observers_)
+    observer.OnDisplaySnapshotsInvalidated();
+}
+
 void DrmNativeDisplayDelegate::Initialize() {
   display_manager_->AddDelegate(this);
 }
 
 void DrmNativeDisplayDelegate::GrabServer() {
 }
 
 void DrmNativeDisplayDelegate::UngrabServer() {
 }
 
@@ skipping 81 matching lines @@
 void DrmNativeDisplayDelegate::RemoveObserver(NativeDisplayObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 display::FakeDisplayController*
 DrmNativeDisplayDelegate::GetFakeDisplayController() {
   return nullptr;
 }
 
 }  // namespace ui