Introduce security_state::ShouldAlwaysShowIcon() for mobile omnibox calculations.

components/security_state/core/security_state_ui.cc

+// Copyright 2016 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 "components/security_state/core/security_state_ui.h"
+
+namespace security_state {
+
+bool ShouldAlwaysShowIcon(SecurityLevel security_level) {
+  // Enumerate all |SecurityLevel| values for compile-time enforcement that all
+  // cases are explicitly handled.
+  switch (security_level) {
+    case NONE:
+      return false;
+    case HTTP_SHOW_WARNING:
+    case EV_SECURE:
+    case SECURE:
+    case SECURITY_WARNING:
+    case SECURE_WITH_POLICY_INSTALLED_CERT:
+    case DANGEROUS:
+      return true;
+  }
+  NOTREACHED();
+  return false;
+}
+
+}  // namespace security_state