[views] Eliminate OnWidgetClosing from NudgeWidgetObserver

Favor OnWidgetDestroying over OnWidgetClosing. OnWidgetClosing is
only called where a Widget is closed directly, it fails to catch
the case when the system destroys the NativeWidget directly. This
can result in UAFs in situations where the OS directly destroys
the widget.

OnWidgetDestroying will be called every time a widget is destroyed
and should be used instead in most cases.

Bug: 1240365
Change-Id: I043635fcfcc9a52dd68b21f4f9c37539bc0d7f34
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3641295
Reviewed-by: Ahmed Mehfooz <amehfooz@chromium.org>
Commit-Queue: Thomas Lukaszewicz <tluk@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1002735}

Author: Tom Lukaszewicz

ash/system/power/adaptive_charging_nudge_controller_unittest.cc

@@ -32,13 +32,13 @@ class NudgeWidgetObserver : public views::WidgetObserver {
     widget_observation_.Observe(widget);
   }
 
-  void WaitForClose() {
+  void WaitForDestruction() {
     run_loop_ = std::make_unique<base::RunLoop>();
     run_loop_->Run();
   }
 
   // views::WidgetObserver:
-  void OnWidgetClosing(views::Widget* widget) override {
+  void OnWidgetDestroying(views::Widget* widget) override {
     if (run_loop_)
       run_loop_->Quit();
   }
@@ -75,8 +75,8 @@ class AdaptiveChargingNudgeControllerTest : public AshTestBase {
 
   AdaptiveChargingNudgeController* GetController() { return controller_.get(); }
 
-  void WaitForWidgetClose(AdaptiveChargingNudgeController* controller,
-                          SystemNudge* nudge) {
+  void WaitForWidgetDestruction(AdaptiveChargingNudgeController* controller,
+                                SystemNudge* nudge) {
     views::Widget* nudge_widget = nudge->widget();
     ASSERT_TRUE(nudge_widget);
     EXPECT_FALSE(nudge_widget->IsClosed());
@@ -86,12 +86,12 @@ class AdaptiveChargingNudgeControllerTest : public AshTestBase {
         ui::ScopedAnimationDurationScaleMode::SLOW_DURATION);
 
     // Pretend the hide nudge timer has elapsed.
-    NudgeWidgetObserver widget_close_observer(nudge_widget);
+    NudgeWidgetObserver widget_destruction_observer(nudge_widget);
     controller->FireHideNudgeTimerForTesting();
 
     EXPECT_TRUE(nudge_widget->GetLayer()->GetAnimator()->is_animating());
 
-    widget_close_observer.WaitForClose();
+    widget_destruction_observer.WaitForDestruction();
   }
 
  private:
@@ -109,7 +109,7 @@ TEST_F(AdaptiveChargingNudgeControllerTest, ShowsAndHidesNudge) {
   SystemNudge* nudge = controller->GetSystemNudgeForTesting();
   ASSERT_TRUE(nudge);
 
-  WaitForWidgetClose(controller, nudge);
+  WaitForWidgetDestruction(controller, nudge);
 }
 
 TEST_F(AdaptiveChargingNudgeControllerTest, NoNudgeShowForDisabledFeature) {
@@ -135,7 +135,7 @@ TEST_F(AdaptiveChargingNudgeControllerTest, NudgeShowExactlyOnce) {
   controller->GetNudgeDelayTimerForTesting()->FireNow();
   SystemNudge* nudge1 = controller->GetSystemNudgeForTesting();
   ASSERT_TRUE(nudge1);
-  WaitForWidgetClose(controller, nudge1);
+  WaitForWidgetDestruction(controller, nudge1);
 
   // No nudge for the second time.
   controller->ShowNudge();