Implement ProcessReusePolicy for SiteInstances

content/browser/browsing_instance.cc

Index: content/browser/browsing_instance.cc
diff --git a/content/browser/browsing_instance.cc b/content/browser/browsing_instance.cc
index 5dd0ca4191fe832c5d4eea078c9cab946a8d397b..ac514919132fa2133c9902f1b7966d19cd9f6dd1 100644
--- a/content/browser/browsing_instance.cc
+++ b/content/browser/browsing_instance.cc
@@ -51,7 +51,8 @@ BrowsingInstance::GetDefaultSubframeSiteInstance() {
   CHECK(SiteIsolationPolicy::IsTopDocumentIsolationEnabled());
   if (!default_subframe_site_instance_) {
     SiteInstanceImpl* instance = new SiteInstanceImpl(this);
-    instance->set_is_default_subframe_site_instance();
+    instance->set_process_reuse_policy(
+        SiteInstanceImpl::ProcessReusePolicy::USE_DEFAULT_SUBFRAME_PROCESS);
 
     // TODO(nick): This is a hack for now.
     instance->SetSite(GURL("http://web-subframes.invalid"));