Cancel dialogs for Tabs when they are removed from their TabModels.

ios/chrome/browser/ui/browser_view_controller.mm

 // Copyright 2012 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.
 
 #import "ios/chrome/browser/ui/browser_view_controller.h"
 
 #import <AssetsLibrary/AssetsLibrary.h>
 #import <MobileCoreServices/MobileCoreServices.h>
 #import <PassKit/PassKit.h>
 #import <Photos/Photos.h>
@@ skipping 4614 matching lines @@
   if (self.active && model.currentTab == newTab)
     [self displayTab:newTab isNewSelection:NO];
 }
 
 // A tab has been removed, remove its views from display if necessary.
 - (void)tabModel:(TabModel*)model
     didRemoveTab:(Tab*)tab
          atIndex:(NSUInteger)index {
   [self uninstallDelegatesForTab:tab];
 
+  // Cancel dialogs for |tab|'s WebState.
+  [self.dialogPresenter cancelDialogForWebState:tab.webState];
+
   // Remove stored native controllers for the tab.
   [_nativeControllersForTabIDs removeObjectForKey:tab.tabId];
 
   // Ignore changes while the tab stack view is visible (or while suspended).
   // The display will be refreshed when this view becomes active again.
   if (!self.visible || !model.webUsageEnabled)
     return;
 
   // Remove the find bar for now.
   [self hideFindBarWithAnimation:NO];
@@ skipping 537 matching lines @@
 
 - (UIView*)voiceSearchButton {
   return _voiceSearchButton;
 }
 
 - (id<LogoAnimationControllerOwner>)logoAnimationControllerOwner {
   return [self currentLogoAnimationControllerOwner];
 }
 
 @end