Why this CL triggers an OilPan crash.

content/browser/site_instance_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
 #define CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 51 matching lines @@
   // URL does not have a valid registered domain, then the full hostname is
   // stored.
   void SetSite(const GURL& url);
   bool HasSite() const;
 
   // Returns whether there is currently a related SiteInstance (registered with
   // BrowsingInstance) for the site of the given url.  If so, we should try to
   // avoid dedicating an unused SiteInstance to it (e.g., in a new tab).
   bool HasRelatedSiteInstance(const GURL& url);
 
+  // Gets an ID of the BrowsingInstance this object is associated with.
+  int GetBrowsingInstanceId() const;
+
   // Returns whether this SiteInstance has a process that is the wrong type for
   // the given URL.  If so, the browser should force a process swap when
   // navigating to the URL.
   bool HasWrongProcessForURL(const GURL& url);
 
   // Increase the number of active frames in this SiteInstance. This is
   // increased when a frame is created, or a currently swapped out frame
   // is swapped in.
   void IncrementActiveFrameCount();
 
@@ skipping 104 matching lines @@
   bool is_default_subframe_site_instance_;
 
   base::ObserverList<Observer, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(SiteInstanceImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_