Add feature flag for SSL committed interstitials on iOS

Bug: 987407
Change-Id: Ifaa7d2fc1066ef6fe033bf1e93d9bce4284b682b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1717426Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Livvie Lin <livvielin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#680622}

ios/web/common/features.h

@@ -38,6 +38,9 @@ extern const base::Feature kBlockUniversalLinksInOffTheRecordMode;
 // Used to ensure that the render is not suspended.
 extern const base::Feature kKeepsRenderProcessAlive;
 
+// Used to enable committed interstitials for SSL errors.
+extern const base::Feature kSSLCommittedInterstitials;
+
 }  // namespace features
 }  // namespace web
 

ios/web/common/features.mm

@@ -35,5 +35,8 @@ const base::Feature kBlockUniversalLinksInOffTheRecordMode{
 const base::Feature kKeepsRenderProcessAlive{"KeepsRenderProcessAlive",
                                              base::FEATURE_ENABLED_BY_DEFAULT};
 
+const base::Feature kSSLCommittedInterstitials{
+    "SSLCommittedInterstitials", base::FEATURE_DISABLED_BY_DEFAULT};
+
 }  // namespace features
 }  // namespace web