[ios] Added DialogsSuppression public API to WebState.

ios/web/web_state/web_state_impl.mm

Index: ios/web/web_state/web_state_impl.mm
diff --git a/ios/web/web_state/web_state_impl.mm b/ios/web/web_state/web_state_impl.mm
index 1a56c66c858983a73fcbbd03ba6dfa40b3949501..0c3561a157b3d00e6ed8fedfaa935679171ec013 100644
--- a/ios/web/web_state/web_state_impl.mm
+++ b/ios/web/web_state/web_state_impl.mm
@@ -539,6 +539,14 @@ void WebStateImpl::SetWebUsageEnabled(bool enabled) {
   [web_controller_ setWebUsageEnabled:enabled];
 }
 
+bool WebStateImpl::ShouldSuppressDialogs() const {
+  return [web_controller_ shouldSuppressDialogs];
+}
+
+void WebStateImpl::SetShouldSuppressDialogs(bool should_suppress) {
+  [web_controller_ setShouldSuppressDialogs:should_suppress];
+}
+
 UIView* WebStateImpl::GetView() {
   return [web_controller_ view];
 }