Virtual destructors should have virtual keyword.

chrome/browser/sync/glue/http_bridge.h

 // Copyright (c) 2011 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 CHROME_BROWSER_SYNC_GLUE_HTTP_BRIDGE_H_
 #define CHROME_BROWSER_SYNC_GLUE_HTTP_BRIDGE_H_
 #pragma once
 
 #include <string>
 
@@ skipping 43 matching lines @@
 
     virtual const std::string& GetUserAgent(const GURL& url) const {
       // If the user agent is set explicitly return that, otherwise call the
       // base class method to return default value.
       return user_agent_.empty() ?
           net::URLRequestContext::GetUserAgent(url) : user_agent_;
     }
 
    private:
     // The destructor MUST be called on the IO thread.
-    ~RequestContext();
+    virtual ~RequestContext();
 
     std::string user_agent_;
     net::URLRequestContext* baseline_context_;
 
     DISALLOW_COPY_AND_ASSIGN(RequestContext);
   };
 
   // Lazy-getter for RequestContext objects.
   class RequestContextGetter : public net::URLRequestContextGetter {
    public:
     explicit RequestContextGetter(
         net::URLRequestContextGetter* baseline_context_getter);
 
     void set_user_agent(const std::string& ua) { user_agent_ = ua; }
     bool is_user_agent_set() const { return !user_agent_.empty(); }
 
     // net::URLRequestContextGetter implementation.
     virtual net::URLRequestContext* GetURLRequestContext();
     virtual scoped_refptr<base::MessageLoopProxy> GetIOMessageLoopProxy() const;
 
    private:
-    ~RequestContextGetter() {}
+    virtual ~RequestContextGetter() {}
 
     // User agent to apply to the net::URLRequestContext.
     std::string user_agent_;
 
     scoped_refptr<net::URLRequestContextGetter> baseline_context_getter_;
 
     // Lazily initialized by GetURLRequestContext().
     scoped_refptr<RequestContext> context_;
 
     DISALLOW_COPY_AND_ASSIGN(RequestContextGetter);
@@ skipping 121 matching lines @@
   HttpBridge::RequestContextGetter* GetRequestContextGetter();
 
   scoped_refptr<HttpBridge::RequestContextGetter> request_context_getter_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpBridgeFactory);
 };
 
 }  //  namespace browser_sync
 
 #endif  // CHROME_BROWSER_SYNC_GLUE_HTTP_BRIDGE_H_