Allow the external protocol dialog to handle FORM_SUBMIT navigation

chrome/browser/chromeos/arc/arc_navigation_throttle.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/arc_navigation_throttle.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 85 matching lines @@
       // No picker has previously been popped up for this - continue.
       break;
   }
   return HandleRequest();
 }
 
 content::NavigationThrottle::ThrottleCheckResult
 ArcNavigationThrottle::HandleRequest() {
   const GURL& url = navigation_handle()->GetURL();
 
-  if (ShouldIgnoreNavigation(navigation_handle()->GetPageTransition()))
+  // Always handle http(s) <form> submissions in Chrome for two reasons: 1) we
+  // don't have a way to send POST data to ARC, and 2) intercepting http(s) form
+  // submissions is not very important because such submissions are usually
+  // done within the same domain. ShouldOverrideUrlLoading() below filters out
+  // such submissions anyway.
+  constexpr bool kAllowFormSubmit = false;
+
+  if (ShouldIgnoreNavigation(navigation_handle()->GetPageTransition(),
+                             kAllowFormSubmit))
     return content::NavigationThrottle::PROCEED;
 
   const GURL previous_url = navigation_handle()->GetReferrer().url;
   const GURL current_url = navigation_handle()->GetURL();
   if (!ShouldOverrideUrlLoading(previous_url, current_url))
     return content::NavigationThrottle::PROCEED;
 
   arc::ArcServiceManager* arc_service_manager = arc::ArcServiceManager::Get();
   DCHECK(arc_service_manager);
   scoped_refptr<arc::LocalActivityResolver> local_resolver =
@@ skipping 157 matching lines @@
 }
 
 // static
 bool ArcNavigationThrottle::ShouldOverrideUrlLoadingForTesting(
     const GURL& previous_url,
     const GURL& current_url) {
   return ShouldOverrideUrlLoading(previous_url, current_url);
 }
 
 }  // namespace arc