New WebContents created via ctrl-click should be in a new process.

chrome/browser/extensions/api/tabs/tabs_api.cc

 // Copyright (c) 2012 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/extensions/api/tabs/tabs_api.h"
 
 #include <stddef.h>
 #include <algorithm>
 #include <limits>
 #include <memory>
@@ skipping 603 matching lines @@
     create_params.initial_show_state =
         ConvertToWindowShowState(create_data->state);
   }
 
   Browser* new_window = new Browser(create_params);
 
   for (const GURL& url : urls) {
     chrome::NavigateParams navigate_params(new_window, url,
                                            ui::PAGE_TRANSITION_LINK);
     navigate_params.disposition = WindowOpenDisposition::NEW_FOREGROUND_TAB;
+
+    // Make sure that (if possible) the new contents are created in the same
+    // renderer process as the caller of the chrome.windows.create API.
+    navigate_params.use_new_renderer_for_new_contents = false;

[Devlin, 2017/04/20 16:22:30]

This is probably checked later, but maybe we should set this to be true iff
|url| is within the extension?  (At the very least, we should document why this
is safe, since at first glance it looks scary.)

[Łukasz Anforowicz, 2017/04/20 19:03:57]

1. Note that the current CL doesn't change the behavior here (although the
change above makes it more explicit what is going on).

2. I've reworded the comment above to make it clearer what is going on.

3. I've also changed |use_new_renderer_for_new_contents| into
|force_new_renderer_for_new_contents| - hopefully this better conveys that we
might still use a new renderer (for cross-site contents) even if
|force_new_renderer_for_new_contents| is false.

     navigate_params.source_site_instance =
         render_frame_host()->GetSiteInstance();
+
     chrome::Navigate(&navigate_params);
   }
 
   WebContents* contents = NULL;
   // Move the tab into the created window only if it's an empty popup or it's
   // a tabbed window.
   if ((window_type == Browser::TYPE_POPUP && urls.empty()) ||
       window_type == Browser::TYPE_TABBED) {
     if (source_tab_strip)
       contents = source_tab_strip->DetachWebContentsAt(tab_index);
@@ skipping 1500 matching lines @@
       params->tab_id
           ? ErrorUtils::FormatErrorMessage(keys::kCannotDiscardTab,
                                            base::IntToString(*params->tab_id))
           : keys::kCannotFindTabToDiscard));
 }
 
 TabsDiscardFunction::TabsDiscardFunction() {}
 TabsDiscardFunction::~TabsDiscardFunction() {}
 
 }  // namespace extensions