PlzNavigate: Fix ordering of onBeforeNavigate and onCreatedNavigationTarget.

chrome/browser/extensions/api/web_navigation/web_navigation_api.cc

Index: chrome/browser/extensions/api/web_navigation/web_navigation_api.cc
diff --git a/chrome/browser/extensions/api/web_navigation/web_navigation_api.cc b/chrome/browser/extensions/api/web_navigation/web_navigation_api.cc
index 6d45ec5856295bb365085ebcbf3cdc14a43bc81d..652994bd6511db87becf1201f744dd75d3d69272 100644
--- a/chrome/browser/extensions/api/web_navigation/web_navigation_api.cc
+++ b/chrome/browser/extensions/api/web_navigation/web_navigation_api.cc
@@ -271,11 +271,27 @@ void WebNavigationTabObserver::DidStartNavigation(
     return;
   }
 
-  helpers::DispatchOnBeforeNavigate(navigation_handle);
+  pending_on_before_navigate_event_ =
+      helpers::CreateOnBeforeNavigateEvent(navigation_handle);
+
+  // Only dispatch the onBeforeNavigate event if the associated WebContents
+  // is already added to the tab strip. Otherwise the event should be delayed
+  // and sent after the addition, to preserve the ordering of events.
+  if (ExtensionTabUtil::GetTabById(ExtensionTabUtil::GetTabId(web_contents()),
+                                   web_contents()->GetBrowserContext(), false,
+                                   nullptr, nullptr, nullptr, nullptr)) {
+    DispatchCachedOnBeforeNavigate();
+  }
 }
 
 void WebNavigationTabObserver::DidFinishNavigation(
     content::NavigationHandle* navigation_handle) {
+  // If there has been a DidStartNavigation call before the tab was ready to
+  // dispatch events, ensure that it is sent before processing the
+  // DidFinishNavigation.
+  // Note: This is exercised by WebNavigationApiTest.TargetBlankIncognito.
+  DispatchCachedOnBeforeNavigate();
+
   if (navigation_handle->HasCommitted() && !navigation_handle->IsErrorPage()) {
     HandleCommit(navigation_handle);
     return;
@@ -391,6 +407,14 @@ void WebNavigationTabObserver::WebContentsDestroyed() {
   registrar_.RemoveAll();
 }
 
+void WebNavigationTabObserver::DispatchCachedOnBeforeNavigate() {
+  if (!pending_on_before_navigate_event_.get())
+    return;
+
+  EventRouter::Get(web_contents()->GetBrowserContext())
+      ->BroadcastEvent(std::move(pending_on_before_navigate_event_));
+}
+
 void WebNavigationTabObserver::HandleCommit(
     content::NavigationHandle* navigation_handle) {
   bool is_reference_fragment_navigation = IsReferenceFragmentNavigation(