Hide BrowsingInstance from all but SiteInstance, as intended by design.

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 3003f92b1f501f47098f742333cc120fe00fc8ba..9f30875246076b65f6e6d73f64a89937a7ad4bd2 100644
--- a/content/browser/browsing_instance.cc
+++ b/content/browser/browsing_instance.cc
@@ -97,7 +97,7 @@ SiteInstance* BrowsingInstance::GetSiteInstanceForURL(const GURL& url) {
 }
 
 void BrowsingInstance::RegisterSiteInstance(SiteInstance* site_instance) {
-  DCHECK(site_instance->browsing_instance() == this);
+  DCHECK(site_instance->browsing_instance_ == this);
   DCHECK(site_instance->has_site());
   std::string site = site_instance->site().possibly_invalid_spec();
 
@@ -116,7 +116,7 @@ void BrowsingInstance::RegisterSiteInstance(SiteInstance* site_instance) {
 }
 
 void BrowsingInstance::UnregisterSiteInstance(SiteInstance* site_instance) {
-  DCHECK(site_instance->browsing_instance() == this);
+  DCHECK(site_instance->browsing_instance_ == this);
   DCHECK(site_instance->has_site());
   std::string site = site_instance->site().possibly_invalid_spec();