[iOS] Break retain cycle in InfoBars.

ios/chrome/browser/translate/before_translate_infobar_controller.mm

Index: ios/chrome/browser/translate/before_translate_infobar_controller.mm
diff --git a/ios/chrome/browser/translate/before_translate_infobar_controller.mm b/ios/chrome/browser/translate/before_translate_infobar_controller.mm
index 462ef17ab43d714057479988d2f310030333c780..59e97ee1c5b0853a56195288bf10ffb6af1277fc 100644
--- a/ios/chrome/browser/translate/before_translate_infobar_controller.mm
+++ b/ios/chrome/browser/translate/before_translate_infobar_controller.mm
@@ -7,6 +7,7 @@
 #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"
@@ -172,9 +173,11 @@ - (void)updateInfobarLabelOnView:(InfoBarView*)view {
   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];
+            [weakSelf infobarLinkDidPress:tag];
           }];
 }