Allow the external protocol dialog to handle FORM_SUBMIT navigation

chrome/browser/chromeos/arc/page_transition_util.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 "chrome/browser/chromeos/arc/page_transition_util.h"
 
 namespace arc {
 
-bool ShouldIgnoreNavigation(ui::PageTransition page_transition) {
+bool ShouldIgnoreNavigation(ui::PageTransition page_transition,
+                            bool allow_form_submit) {
   // Mask out server-sided redirects only.
   page_transition = ui::PageTransitionFromInt(
       page_transition & ~ui::PAGE_TRANSITION_SERVER_REDIRECT);
 
   if (!ui::PageTransitionCoreTypeIs(page_transition,
-                                    ui::PAGE_TRANSITION_LINK)) {
+                                    ui::PAGE_TRANSITION_LINK) &&
+      !(allow_form_submit &&
+        ui::PageTransitionCoreTypeIs(page_transition,
+                                     ui::PAGE_TRANSITION_FORM_SUBMIT))) {
     // Do not handle the |url| if this event wasn't spawned by the user clicking
     // on a link.
     return true;
   }
 
   if (ui::PageTransitionGetQualifier(page_transition) != 0) {
     // Qualifiers indicate that this navigation was the result of a click on a
     // forward/back button, or typing in the URL bar, or a client-side redirect,
     // etc.  Don't handle any of those types of navigations.
     return true;
   }
 
   return false;
 }
 
 }  // namespace arc