View-source URLs should use a separate SiteInstance in all cases.

content/browser/web_contents/render_view_host_manager.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 "content/browser/web_contents/render_view_host_manager.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/logging.h"
@@ skipping 470 matching lines @@
       return curr_site_instance->GetRelatedSiteInstance(dest_url);
     }
 
     // For extensions, Web UI URLs (such as the new tab page), and apps we do
     // not want to use the curr_instance if it has no site, since it will have a
     // RenderProcessHost of PRIV_NORMAL.  Create a new SiteInstance for this
     // URL instead (with the correct process type).
     if (curr_site_instance->HasWrongProcessForURL(dest_url))
       return curr_site_instance->GetRelatedSiteInstance(dest_url);
 
+    // View-source URLs must use a new SiteInstance and BrowsingInstance.
+    // TODO(nasko): This is the same condition as later in the function. This
+    // should be taken into account when refactoring this method as part of
+    // http://crbug.com/123007.
+    if (entry.IsViewSourceMode())
+      return SiteInstance::CreateForURL(browser_context, dest_url);
+
     // Normally the "site" on the SiteInstance is set lazily when the load
     // actually commits. This is to support better process sharing in case
     // the site redirects to some other site: we want to use the destination
     // site in the site instance.
     //
     // In the case of session restore, as it loads all the pages immediately
     // we need to set the site first, otherwise after a restore none of the
     // pages would share renderers in process-per-site.
     if (entry.restore_type() != NavigationEntryImpl::RESTORE_NONE)
       curr_site_instance->SetSite(dest_url);
@@ skipping 413 matching lines @@
 }
 
 RenderViewHost* RenderViewHostManager::GetSwappedOutRenderViewHost(
     SiteInstance* instance) {
   RenderViewHostMap::iterator iter = swapped_out_hosts_.find(instance->GetId());
   if (iter != swapped_out_hosts_.end())
     return iter->second;
 
   return NULL;
 }