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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 0cb80ac80a986940d242d23f538a8460c6bde2dc..8a667cf0ffd2a3f5d104c9c4430d172f9db099c6 100644
--- a/content/browser/browsing_instance.h
+++ b/content/browser/browsing_instance.h
@@ -73,6 +73,12 @@ class CONTENT_EXPORT BrowsingInstance
   // SiteInstance per site.
   SiteInstance* GetSiteInstanceForURL(const GURL& url);
 
+  // Returns a SiteInstance that should be used for subframes when an oopif is
+  // required, but a dedicated process is not. This SiteInstance will be created
+  // if it doesn't already exist. There is at most one of these per
+  // BrowsingInstance.
+  SiteInstance* GetDefaultSubframeSiteInstance();
+
   // Adds the given SiteInstance to our map, to ensure that we do not create
   // another SiteInstance for the same site.
   void RegisterSiteInstance(SiteInstance* site_instance);
@@ -120,6 +126,8 @@ class CONTENT_EXPORT BrowsingInstance
   // Number of WebContentses currently using this BrowsingInstance.
   size_t active_contents_count_;
 
+  SiteInstance* default_subframe_site_instance_ = nullptr;
+
   DISALLOW_COPY_AND_ASSIGN(BrowsingInstance);
 };