[iOS] Break retain cycle in InfoBars.

ios/chrome/browser/translate/before_translate_infobar_controller.mm

 // Copyright 2013 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 "ios/chrome/browser/translate/before_translate_infobar_controller.h"
 
 #include <stddef.h>
 #import <UIKit/UIKit.h>
 
+#include "base/ios/weak_nsobject.h"
 #include "base/logging.h"
 #include "base/mac/scoped_nsobject.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/strings/grit/components_strings.h"
 #include "components/translate/core/browser/translate_infobar_delegate.h"
 #include "ios/chrome/browser/translate/translate_infobar_tags.h"
 #import "ios/chrome/browser/ui/infobars/infobar_view.h"
 #import "ios/chrome/browser/ui/infobars/infobar_view_delegate.h"
 #include "ui/base/l10n/l10n_util.h"
@@ skipping 145 matching lines @@
   base::string16 originalLanguageWithLink =
       base::SysNSStringToUTF16([[view class]
           stringAsLink:originalLanguage
                    tag:TranslateInfoBarIOSTag::BEFORE_SOURCE_LANGUAGE]);
   base::string16 targetLanguageWithLink = base::SysNSStringToUTF16([[view class]
       stringAsLink:targetLanguage
                tag:TranslateInfoBarIOSTag::BEFORE_TARGET_LANGUAGE]);
   NSString* label =
       l10n_util::GetNSStringF(IDS_TRANSLATE_INFOBAR_BEFORE_MESSAGE_IOS,
                               originalLanguageWithLink, targetLanguageWithLink);
+
+  base::WeakNSObject<BeforeTranslateInfoBarController> weakSelf(self);
   [view addLabel:label
           action:^(NSUInteger tag) {
-            [self infobarLinkDidPress:tag];
+            base::scoped_nsobject<BeforeTranslateInfoBarController> strongSelf(
+                [weakSelf retain]);
+            [strongSelf infobarLinkDidPress:tag];

[sdefresne, 2017/06/12 14:14:24]

ditto

           }];
 }
 
 - (void)languageSelectionDone {
   size_t selectedRow = [_languagePicker selectedRowInComponent:0];
   std::string lang = _translateInfoBarDelegate->language_code_at(selectedRow);
   if (_languageSelectionType ==
           TranslateInfoBarIOSTag::BEFORE_SOURCE_LANGUAGE &&
       lang != _translateInfoBarDelegate->target_language_code()) {
     _translateInfoBarDelegate->UpdateOriginalLanguage(lang);
@@ skipping 178 matching lines @@
   [super removeView];
   [self dismissLanguageSelectionView];
 }
 
 - (void)detachView {
   [super detachView];
   [self dismissLanguageSelectionView];
 }
 
 @end