Fix use after free for cached_displays_.

ui/display/manager/chromeos/display_configurator.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/display/manager/chromeos/display_configurator.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 506 matching lines @@
 
 void DisplayConfigurator::Init(
     std::unique_ptr<NativeDisplayDelegate> display_delegate,
     bool is_panel_fitting_enabled) {
   is_panel_fitting_enabled_ = is_panel_fitting_enabled;
   if (!configure_display_ || display_externally_controlled_)
     return;
 
   // If the delegate is already initialized don't update it (For example, tests
   // set their own delegates).
-  if (!native_display_delegate_) {
+  if (!native_display_delegate_)
     native_display_delegate_ = std::move(display_delegate);
-    native_display_delegate_->AddObserver(this);
-  }
+
+  native_display_delegate_->AddObserver(this);
 }
 
 void DisplayConfigurator::TakeControl(const DisplayControlCallback& callback) {
   if (display_control_changing_) {
     callback.Run(false);
     return;
   }
 
   if (!display_externally_controlled_) {
     callback.Run(true);
@@ skipping 399 matching lines @@
     return;
   }
 
   // Configure displays with |kConfigureDelayMs| delay,
   // so that time-consuming ConfigureDisplays() won't be called multiple times.
   configure_timer_.Start(FROM_HERE,
                          base::TimeDelta::FromMilliseconds(kConfigureDelayMs),
                          this, &DisplayConfigurator::ConfigureDisplays);
 }
 
+void DisplayConfigurator::OnDisplaySnapshotsInvalidated() {
+  VLOG(1) << "Display snapshots invalidated.";
+  cached_displays_.clear();
+}
+
 void DisplayConfigurator::AddObserver(Observer* observer) {
   observers_.AddObserver(observer);
 }
 
 void DisplayConfigurator::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void DisplayConfigurator::SuspendDisplays(
     const ConfigurationCallback& callback) {
@@ skipping 227 matching lines @@
   last_virtual_display_id_ = max_display_id & 0xff;
 
   return true;
 }
 
 bool DisplayConfigurator::IsDisplayOn() const {
   return current_power_state_ != chromeos::DISPLAY_POWER_ALL_OFF;
 }
 
 }  // namespace ui