PlzNavigate: fix timing issue in app window creation

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index a93eea7e70809ddf518856e59d4eeb4eb79a8e96..456de00fc7e9c0d8eb9b7efceb193317896ba0c1 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -2788,6 +2788,12 @@ void WebContentsImpl::DidRedirectNavigation(
                     DidRedirectNavigation(navigation_handle));
 }
 
+void WebContentsImpl::ReadyToCommitNavigation(
+    NavigationHandle* navigation_handle) {
+  FOR_EACH_OBSERVER(WebContentsObserver, observers_,
+                    ReadyToCommitNavigation(navigation_handle));
+}
+
 void WebContentsImpl::DidCommitNavigation(NavigationHandle* navigation_handle) {
   FOR_EACH_OBSERVER(WebContentsObserver, observers_,
                     DidCommitNavigation(navigation_handle));