[ios] ios/web_view base::Bind -> base::BindRepeating

Updating base::Bind calls to base::BindRepeating for ios/web_view folder
as part of code health improvements

Bug: 1007796
Change-Id: I266da5b514b6734dfb0c884a749237dd1ce6ab0a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2238370
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Jeff Yoon <jeffyoon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#776990}

ios/web_view/internal/passwords/web_view_password_manager_client.mm

@@ -76,8 +76,8 @@
       password_feature_manager_(pref_service, sync_service),
       credentials_filter_(
           this,
-          base::Bind(&WebViewPasswordManagerClient::GetSyncService,
-                     base::Unretained(this))),
+          base::BindRepeating(&WebViewPasswordManagerClient::GetSyncService,
+                              base::Unretained(this))),
       helper_(this) {
   saving_passwords_enabled_.Init(
       password_manager::prefs::kCredentialsEnableService, GetPrefs());