[ios] Unregister CRWWebController delegates in -close.

ios/web/web_state/ui/crw_web_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/web/web_state/ui/crw_web_controller.h"
 
 #import <WebKit/WebKit.h>
 
 #import <objc/runtime.h>
 #include <stddef.h>
@@ skipping 1015 matching lines @@
 - (void)setDelegate:(id<CRWWebDelegate>)delegate {
   _delegate.reset(delegate);
   if ([self.nativeController respondsToSelector:@selector(setDelegate:)])
     [self.nativeController setDelegate:self];
 }
 
 - (void)dealloc {
   DCHECK([NSThread isMainThread]);
   DCHECK(_isBeingDestroyed);  // 'close' must have been called already.
   DCHECK(!_webView);
-  // TODO(crbug.com/662860): Don't set the delegate to nil.
-  [_containerView setDelegate:nil];
-  if ([self.nativeController respondsToSelector:@selector(setDelegate:)]) {
-    [self.nativeController setDelegate:nil];
-  }
-  _touchTrackingRecognizer.get().touchTrackingDelegate = nil;
-  [[_webViewProxy scrollViewProxy] removeObserver:self];
-  [[NSNotificationCenter defaultCenter] removeObserver:self];
   [super dealloc];
 }
 
 - (void)dismissKeyboard {
   [_webView endEditing:YES];
   if ([self.nativeController respondsToSelector:@selector(dismissKeyboard)])
     [self.nativeController dismissKeyboard];
 }
 
 - (id<CRWNativeContent>)nativeController {
@@ skipping 155 matching lines @@
   DCHECK(!_isBeingDestroyed);
   DCHECK(!_delegate);  // Delegate should reset its association before closing.
   // Mark the destruction sequence has started, in case someone else holds a
   // strong reference and tries to continue using the tab.
   _isBeingDestroyed = YES;
 
   // Remove the web view now. Otherwise, delegate callbacks occur.
   [self removeWebViewAllowingCachedReconstruction:NO];
 
   _webStateImpl = nullptr;
+
+  DCHECK(!_webView);
+  // TODO(crbug.com/662860): Don't set the delegate to nil.
+  [_containerView setDelegate:nil];
+  if ([self.nativeController respondsToSelector:@selector(setDelegate:)]) {
+    [self.nativeController setDelegate:nil];
+  }
+  _touchTrackingRecognizer.get().touchTrackingDelegate = nil;
+  [[_webViewProxy scrollViewProxy] removeObserver:self];
+  [[NSNotificationCenter defaultCenter] removeObserver:self];
 }
 
 // TODO(shreyasv): This code is shared with SnapshotManager. Remove this and add
 // it as part of WebDelegate delegate API such that a default image is returned
 // immediately.
 + (UIImage*)defaultSnapshotImage {
   static UIImage* defaultImage = nil;
 
   if (!defaultImage) {
     CGRect frame = CGRectMake(0, 0, 2, 2);
@@ skipping 3834 matching lines @@
 - (NSUInteger)observerCount {
   DCHECK_EQ(_observerBridges.size(), [_observers count]);
   return [_observers count];
 }
 
 - (NSString*)referrerFromNavigationAction:(WKNavigationAction*)action {
   return [action.request valueForHTTPHeaderField:kReferrerHeaderName];
 }
 
 @end