Ensure that navigation will proceed when no NavigationHandle is found

content/browser/loader/navigation_resource_throttle.cc

 // Copyright 2015 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 "content/browser/loader/navigation_resource_throttle.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ skipping 67 matching lines @@
   if (!render_frame_host) {
     SendCheckResultToIOThread(callback, NavigationThrottle::CANCEL);
     return nullptr;
   }
 
   NavigationHandleImpl* navigation_handle =
       render_frame_host->frame_tree_node()
           ->navigator()
           ->GetNavigationHandleForFrameHost(render_frame_host);
   if (!navigation_handle) {
-    SendCheckResultToIOThread(callback, NavigationThrottle::CANCEL);
+    SendCheckResultToIOThread(callback, NavigationThrottle::PROCEED);
     return nullptr;
   }
   return navigation_handle;
 }
 
 void CheckWillStartRequestOnUIThread(
     UIChecksPerformedCallback callback,
     int render_process_id,
     int render_frame_host_id,
     const std::string& method,
@@ skipping 272 matching lines @@
 
   // If the results of the checks on the UI thread are known, unblock the
   // navigation. Otherwise, wait until the callback has executed.
   if (on_transfer_done_result_ != NavigationThrottle::DEFER) {
     OnUIChecksPerformed(on_transfer_done_result_);
     on_transfer_done_result_ = NavigationThrottle::DEFER;
   }
 }
 
 }  // namespace content