NOT YET READY: Improve granularity of window namespaces in Blink.

content/browser/browsing_instance.h

Index: content/browser/browsing_instance.h
diff --git a/content/browser/browsing_instance.h b/content/browser/browsing_instance.h
index 34c1f073bbd852c260aecf8eade45656d6d10005..ff933fe40c45f5a29c9f6bb45c5027ee7d3d10b1 100644
--- a/content/browser/browsing_instance.h
+++ b/content/browser/browsing_instance.h
@@ -54,6 +54,10 @@ class SiteInstanceImpl;
 // BrowsingInstances and SiteInstances are tested together in
 // site_instance_unittest.cc.
 //
+// Note that a browsing instance in the browser is independently tracked in
+// the renderer inside blink::Page::RelatedPages() method (in theory the browser
+// and renderer should always stay in sync).
+//
 ///////////////////////////////////////////////////////////////////////////////
 class CONTENT_EXPORT BrowsingInstance final
     : public base::RefCounted<BrowsingInstance> {