Simplify RenderFrameImpl::decidePolicyForNavigation and avoid DCHECK

content/renderer/render_frame_impl.cc

 // Copyright 2013 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/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 4961 matching lines @@
     // blessed with file permissions.
     int cumulative_bindings = RenderProcess::current()->GetEnabledBindings();
     bool is_initial_navigation = render_view_->history_list_length_ == 0;
     bool should_fork = HasWebUIScheme(url) || HasWebUIScheme(old_url) ||
                        (cumulative_bindings & BINDINGS_POLICY_WEB_UI) ||
                        url.SchemeIs(kViewSourceScheme) ||
                        (frame_->isViewSourceModeEnabled() &&
                         info.navigationType != blink::WebNavigationTypeReload);
 
     if (!should_fork && url.SchemeIs(url::kFileScheme)) {
-      // Fork non-file to file opens.  Check the opener URL if this is the
-      // initial navigation in a newly opened window.
-      GURL source_url(old_url);
-      if (is_initial_navigation && source_url.is_empty() && frame_->opener())
-        source_url = frame_->opener()->top()->document().url();
-      DCHECK(!source_url.is_empty());
-      should_fork = !source_url.SchemeIs(url::kFileScheme);
+      // Fork non-file to file opens.  Note that this may fork unnecessarily if
+      // another tab (hosting a file or not) targeted this one before its
+      // initial navigation, but that shouldn't cause a problem.
+      should_fork = !old_url.SchemeIs(url::kFileScheme);
     }
 
     if (!should_fork) {
       // Give the embedder a chance.
       should_fork = GetContentClient()->renderer()->ShouldFork(
           frame_, url, info.urlRequest.httpMethod().utf8(),
           is_initial_navigation, is_redirect, &send_referrer);
     }
 
     if (should_fork) {
@@ skipping 1330 matching lines @@
   // event target. Potentially a Pepper plugin will receive the event.
   // In order to tell whether a plugin gets the last mouse event and which it
   // is, we set |pepper_last_mouse_event_target_| to null here. If a plugin gets
   // the event, it will notify us via DidReceiveMouseEvent() and set itself as
   // |pepper_last_mouse_event_target_|.
   pepper_last_mouse_event_target_ = nullptr;
 #endif
 }
 
 }  // namespace content