Prevent GuestView from swapping process on cross-site navigations in --site-per-process.

content/browser/loader/cross_site_resource_handler.cc

Index: content/browser/loader/cross_site_resource_handler.cc
diff --git a/content/browser/loader/cross_site_resource_handler.cc b/content/browser/loader/cross_site_resource_handler.cc
index ebf40eb023a6abfd0047b64e11de9ef04dd57eb7..cb344d4b98532082476919b04d49370642b03df9 100644
--- a/content/browser/loader/cross_site_resource_handler.cc
+++ b/content/browser/loader/cross_site_resource_handler.cc
@@ -16,6 +16,7 @@
 #include "content/browser/loader/resource_dispatcher_host_impl.h"
 #include "content/browser/loader/resource_request_info_impl.h"
 #include "content/browser/site_instance_impl.h"
+#include "content/browser/web_contents/web_contents_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/global_request_id.h"
@@ -99,6 +100,12 @@ bool CheckNavigationPolicyOnUI(GURL url, int process_id, int render_frame_id) {
   if (!rfh->GetSiteInstance()->HasSite())
     return false;
 
+  // For now, GuestViews never transfer on cross-site navigations.
+  WebContentsImpl* web_contents =
+      static_cast<WebContentsImpl*>(WebContents::FromRenderFrameHost(rfh));
+  if (web_contents->GetBrowserPluginGuest())
+    return false;
+
   // TODO(nasko): This check is very simplistic and is used temporarily only
   // for --site-per-process. It should be updated to match the check performed
   // by RenderFrameHostManager::UpdateStateForNavigate.