[ios] Null OverlayRequestCoordinator's delegate when Browser destroyed

If the Browser is destroyed, then OverlayPresentationContextImpl will
soon be as well. Thus, OverlayRequestCoordinator's reference to it
will be invalid, so OverlayPresentationContextImpl should remove
itself as the delegate.

This change also uses __weak references to self
InfobarBannerOverlayCoordaintor.

Bug: 1129962, 1129788
Change-Id: I082ad3f7acf671b61e23434f918d22d900d5227f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2427407Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Chris Lu <thegreenfrog@chromium.org>
Auto-Submit: Chris Lu <thegreenfrog@chromium.org>
Cr-Commit-Position: refs/heads/master@{#810916}

ios/chrome/browser/ui/overlays/infobar_banner/infobar_banner_overlay_coordinator.mm

@@ -102,11 +102,16 @@
   self.bannerTransitionDriver.bannerPositioner = self;
   self.bannerViewController.transitioningDelegate = self.bannerTransitionDriver;
   self.bannerViewController.interactionDelegate = self.bannerTransitionDriver;
-  [self.baseViewController presentViewController:self.viewController
-                                        animated:animated
-                                      completion:^{
-                                        [self finishPresentation];
-                                      }];
+  __weak InfobarBannerOverlayCoordinator* weakSelf = self;
+  [self.baseViewController
+      presentViewController:self.viewController
+                   animated:animated
+                 completion:^{
+                   InfobarBannerOverlayCoordinator* strongSelf = weakSelf;
+                   if (strongSelf) {
+                     [strongSelf finishPresentation];
+                   }
+                 }];
   self.started = YES;
 
   if (!UIAccessibilityIsVoiceOverRunning()) {
@@ -128,10 +133,16 @@
   // Mark started as NO before calling dismissal callback to prevent dup
   // stopAnimated: executions.
   self.started = NO;
-  [self.baseViewController dismissViewControllerAnimated:animated
-                                              completion:^{
-                                                [self finishDismissal];
-                                              }];
+  __weak InfobarBannerOverlayCoordinator* weakSelf = self;
+  [self.baseViewController
+      dismissViewControllerAnimated:animated
+                         completion:^{
+                           InfobarBannerOverlayCoordinator* strongSelf =
+                               weakSelf;
+                           if (strongSelf) {
+                             [strongSelf finishDismissal];
+                           }
+                         }];
 }
 
 - (UIViewController*)viewController {
@@ -145,7 +156,9 @@
   // Notify the presentation context that the presentation has finished.  This
   // is necessary to synchronize OverlayPresenter scheduling logic with the UI
   // layer.
-  self.delegate->OverlayUIDidFinishPresentation(self.request);
+  if (self.delegate) {
+    self.delegate->OverlayUIDidFinishPresentation(self.request);
+  }
   UpdateBannerAccessibilityForPresentation(self.baseViewController,
                                            self.viewController.view);
 }
@@ -160,7 +173,9 @@
   // Notify the presentation context that the dismissal has finished.  This
   // is necessary to synchronize OverlayPresenter scheduling logic with the UI
   // layer.
-  self.delegate->OverlayUIDidFinishDismissal(self.request);
+  if (self.delegate) {
+    self.delegate->OverlayUIDidFinishDismissal(self.request);
+  }
   UpdateBannerAccessibilityForDismissal(self.baseViewController);
 }
 

ios/chrome/browser/ui/overlays/overlay_presentation_context_impl.h

@@ -138,10 +138,15 @@ class OverlayPresentationContextImpl : public OverlayPresentationContext {
   // Called when the UI for |request_| has finished being dismissed.
   void OverlayUIWasDismissed();
 
+  // Called when the Browser is being destroyed.
+  void BrowserDestroyed();
+
   // Helper object that detaches the UI delegate for Browser shudown.
   class BrowserShutdownHelper : public BrowserObserver {
    public:
-    BrowserShutdownHelper(Browser* browser, OverlayPresenter* presenter);
+    BrowserShutdownHelper(Browser* browser,
+                          OverlayPresenter* presenter,
+                          OverlayPresentationContextImpl* presentation_context);
     ~BrowserShutdownHelper() override;
 
     // BrowserObserver:
@@ -150,6 +155,8 @@ class OverlayPresentationContextImpl : public OverlayPresentationContext {
    private:
     // The presenter whose delegate needs to be reset.
     OverlayPresenter* presenter_ = nullptr;
+    // OverlayPresentationContextImpl reference.
+    OverlayPresentationContextImpl* presentation_context_ = nullptr;
   };
 
   // Helper object that listens for UI dismissal events.

ios/chrome/browser/ui/overlays/overlay_presentation_context_impl.mm

@@ -68,7 +68,7 @@ OverlayPresentationContextImpl::OverlayPresentationContextImpl(
     OverlayModality modality,
     OverlayRequestCoordinatorFactory* factory)
     : presenter_(OverlayPresenter::FromBrowser(browser, modality)),
-      shutdown_helper_(browser, presenter_),
+      shutdown_helper_(browser, presenter_, this),
       coordinator_delegate_(this),
       fullscreen_disabler_(browser, modality),
       coordinator_factory_(factory),
@@ -374,12 +374,21 @@ void OverlayPresentationContextImpl::OverlayUIWasDismissed() {
     SetRequest(nullptr);
 }
 
+void OverlayPresentationContextImpl::BrowserDestroyed() {
+  for (std::pair<OverlayRequest* const, std::unique_ptr<OverlayRequestUIState>>&
+           state : states_) {
+    OverlayRequestUIState* ui_state = state.second.get();
+    ui_state->coordinator().delegate = nil;
+  }
+}
+
 #pragma mark BrowserShutdownHelper
 
 OverlayPresentationContextImpl::BrowserShutdownHelper::BrowserShutdownHelper(
     Browser* browser,
-    OverlayPresenter* presenter)
-    : presenter_(presenter) {
+    OverlayPresenter* presenter,
+    OverlayPresentationContextImpl* presentation_context)
+    : presenter_(presenter), presentation_context_(presentation_context) {
   DCHECK(presenter_);
   browser->AddObserver(this);
 }
@@ -390,6 +399,7 @@ OverlayPresentationContextImpl::BrowserShutdownHelper::
 void OverlayPresentationContextImpl::BrowserShutdownHelper::BrowserDestroyed(
     Browser* browser) {
   presenter_->SetPresentationContext(nullptr);
+  presentation_context_->BrowserDestroyed();
   browser->RemoveObserver(this);
 }
 

ios/chrome/browser/ui/overlays/overlay_request_coordinator.h

@@ -38,7 +38,7 @@ class OverlayRequest;
 // communicate when the overlay UI is finished being presented and dismissed.
 // Overlay UI presentation and dismissal may occur after |-start| and |-stop|,
 // even if the overlay is stopped without animation.
-@property(nonatomic, readonly) OverlayRequestCoordinatorDelegate* delegate;
+@property(nonatomic, assign) OverlayRequestCoordinatorDelegate* delegate;
 
 // The request used to configure the overlay UI.
 @property(nonatomic, readonly) OverlayRequest* request;