Remove old session history logic.

content/browser/frame_host/navigator_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/browser/frame_host/navigator_impl.h"
 
 #include <utility>
 
 #include "base/logging.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 733 matching lines @@
   if (!GetContentClient()->browser()->ShouldAllowOpenURL(
           current_site_instance, url)) {
     dest_url = GURL(url::kAboutBlankURL);
   }
 
   int frame_tree_node_id = -1;
 
   // Send the navigation to the current FrameTreeNode if it's destined for a
   // subframe in the current tab.  We'll assume it's for the main frame
   // (possibly of a new or different WebContents) otherwise.
-  if (SiteIsolationPolicy::UseSubframeNavigationEntries() &&
-      disposition == WindowOpenDisposition::CURRENT_TAB &&
+  if (disposition == WindowOpenDisposition::CURRENT_TAB &&
       render_frame_host->GetParent()) {
     frame_tree_node_id =
         render_frame_host->frame_tree_node()->frame_tree_node_id();
   }
 
   OpenURLParams params(dest_url, referrer, frame_tree_node_id, disposition,
                        ui::PAGE_TRANSITION_LINK,
                        true /* is_renderer_initiated */);
   params.uses_post = uses_post;
   params.post_data = body;
@@ skipping 94 matching lines @@
   // entry.  Subframe transfers should only be possible in OOPIF-enabled modes,
   // and should have a clone of the last committed entry with a
   // FrameNavigationEntry for the target frame.  Main frame transfers should
   // have a new NavigationEntry.
   // TODO(creis): Make this unnecessary by creating (and validating) the params
   // directly, passing them to the destination RenderFrameHost.  See
   // https://crbug.com/536906.
   std::unique_ptr<NavigationEntryImpl> entry;
   if (!node->IsMainFrame()) {
     // Subframe case: create FrameNavigationEntry.
-    CHECK(SiteIsolationPolicy::UseSubframeNavigationEntries());
     if (controller_->GetLastCommittedEntry()) {
       entry = controller_->GetLastCommittedEntry()->Clone();
       entry->set_extra_headers(extra_headers);
     } else {
       // If there's no last committed entry, create an entry for about:blank
       // with a subframe entry for our destination.
       // TODO(creis): Ensure this case can't exist in https://crbug.com/524208.
       entry = NavigationEntryImpl::FromNavigationEntry(
           controller_->CreateNavigationEntry(
               GURL(url::kAboutBlankURL), referrer_to_use, page_transition,
@@ skipping 389 matching lines @@
     if (navigation_handle)
       navigation_handle->update_entry_id_for_transfer(entry->GetUniqueID());
 
     controller_->SetPendingEntry(std::move(entry));
     if (delegate_)
       delegate_->NotifyChangedNavigationState(content::INVALIDATE_TYPE_URL);
   }
 }
 
 }  // namespace content