Disable cross-process navigations in --single-process.

content/browser/frame_host/render_frame_host_manager.h

 // 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.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_MANAGER_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_MANAGER_H_
 
 #include <stdint.h>
 
 #include <list>
@@ skipping 542 matching lines @@
     SiteInstanceRelation relation;
   };
 
   // Create a RenderFrameProxyHost owned by this object.
   RenderFrameProxyHost* CreateRenderFrameProxyHost(SiteInstance* site_instance,
                                                    RenderViewHostImpl* rvh);
   // Delete a RenderFrameProxyHost owned by this object.
   void DeleteRenderFrameProxyHost(SiteInstance* site_instance);
 
   // Returns whether this tab should transition to a new renderer for
-  // cross-site URLs.  Enabled unless we see the --process-per-tab command line
-  // switch.  Can be overridden in unit tests.
+  // cross-site URLs.  Enabled unless we see the --single-process command line
+  // switch.
   bool ShouldTransitionCrossSite();
 
   // Returns true if for the navigation from |current_effective_url| to
   // |new_effective_url|, a new SiteInstance and BrowsingInstance should be
   // created (even if we are in a process model that doesn't usually swap).
   // This forces a process swap and severs script connections with existing
   // tabs.  Cases where this can happen include transitions between WebUI and
   // regular web pages. |new_site_instance| may be null.
   // If there is no current NavigationEntry, then |current_is_view_source_mode|
   // should be the same as |new_is_view_source_mode|.
@@ skipping 231 matching lines @@
   std::unique_ptr<RenderFrameHostImpl> speculative_render_frame_host_;
 
   base::WeakPtrFactory<RenderFrameHostManager> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameHostManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_MANAGER_H_