Update content/ to use scoped_refptr<T>::get() rather than implicit "operator T*"

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 d10ea209b2f0bd44bc9be0959c3524a9155db5e3..c70f38b9daaf5b32d64799e439b5b391024a5552 100644
--- a/content/browser/browsing_instance.cc
+++ b/content/browser/browsing_instance.cc
@@ -45,8 +45,9 @@ SiteInstance* BrowsingInstance::GetSiteInstanceForURL(const GURL& url) {
 }
 
 void BrowsingInstance::RegisterSiteInstance(SiteInstance* site_instance) {
-  DCHECK(static_cast<SiteInstanceImpl*>(site_instance)->
-         browsing_instance_ == this);
+  DCHECK(static_cast<SiteInstanceImpl*>(site_instance)
+             ->browsing_instance_.get() ==
+         this);
   DCHECK(static_cast<SiteInstanceImpl*>(site_instance)->HasSite());
   std::string site = site_instance->GetSiteURL().possibly_invalid_spec();
 
@@ -63,8 +64,9 @@ void BrowsingInstance::RegisterSiteInstance(SiteInstance* site_instance) {
 }
 
 void BrowsingInstance::UnregisterSiteInstance(SiteInstance* site_instance) {
-  DCHECK(static_cast<SiteInstanceImpl*>(site_instance)->
-         browsing_instance_ == this);
+  DCHECK(static_cast<SiteInstanceImpl*>(site_instance)
+             ->browsing_instance_.get() ==
+         this);
   DCHECK(static_cast<SiteInstanceImpl*>(site_instance)->HasSite());
   std::string site = site_instance->GetSiteURL().possibly_invalid_spec();