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

content/browser/site_instance_impl.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/site_instance_impl.h"
 
+#include "base/command_line.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
 #include "content/browser/browsing_instance.h"
 #include "content/browser/child_process_security_policy_impl.h"
 #include "content/browser/frame_host/debug_urls.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/storage_partition_impl.h"
 #include "content/common/site_isolation_policy.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/render_process_host_factory.h"
 #include "content/public/browser/web_ui_controller_factory.h"
+#include "content/public/common/content_switches.h"
 #include "content/public/common/url_constants.h"
 #include "net/base/registry_controlled_domains/registry_controlled_domain.h"
 
 namespace content {
 
 int32_t SiteInstanceImpl::next_site_instance_id_ = 1;
 
 SiteInstanceImpl::SiteInstanceImpl(BrowsingInstance* browsing_instance)
     : id_(next_site_instance_id_++),
       active_frame_count_(0),
@@ skipping 379 matching lines @@
           browser_context, site_url)) {
     return true;
   }
 
   return false;
 }
 
 // static
 bool SiteInstanceImpl::ShouldLockToOrigin(BrowserContext* browser_context,
                                           GURL site_url) {
+  // Don't lock to origin in --single-process or --process-per-tab modes, since
+  // these modes put cross-site pages into the same process.
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kSingleProcess) ||
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kProcessPerTab))
+    return false;
+
   if (!DoesSiteRequireDedicatedProcess(browser_context, site_url))
     return false;
 
   // Guest processes cannot be locked to their site because guests always have
   // a fixed SiteInstance. The site of GURLs a guest loads doesn't match that
   // SiteInstance. So we skip locking the guest process to the site.
   // TODO(ncarter): Remove this exclusion once we can make origin lock per
   // RenderFrame routing id.
   if (site_url.SchemeIs(content::kGuestScheme))
     return false;
@@ skipping 56 matching lines @@
   // prevent the non-isolated sites from requesting resources for isolated
   // sites. https://crbug.com/509125
   if (ShouldLockToOrigin(GetBrowserContext(), site_)) {
     ChildProcessSecurityPolicyImpl* policy =
         ChildProcessSecurityPolicyImpl::GetInstance();
     policy->LockToOrigin(process_->GetID(), site_);
   }
 }
 
 }  // namespace content