net: Fix more clang warnings about missing virtual and OVERRIDE annotations.

net/disk_cache/entry_impl.cc

 // 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.
 
 #include "net/disk_cache/entry_impl.h"
 
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/string_util.h"
 #include "net/base/io_buffer.h"
@@ skipping 22 matching lines @@
   // |end_event_type| is the event type to log on completion.  Logs nothing on
   // discard, or when the NetLog is not set to log all events.
   SyncCallback(disk_cache::EntryImpl* entry, net::IOBuffer* buffer,
                const net::CompletionCallback& callback,
                net::NetLog::EventType end_event_type)
       : entry_(entry), callback_(callback), buf_(buffer),
         start_(TimeTicks::Now()), end_event_type_(end_event_type) {
     entry->AddRef();
     entry->IncrementIoCount();
   }
-  ~SyncCallback() {}
+  virtual ~SyncCallback() {}
 
-  virtual void OnFileIOComplete(int bytes_copied);
+  virtual void OnFileIOComplete(int bytes_copied) OVERRIDE;
   void Discard();
 
  private:
   disk_cache::EntryImpl* entry_;
   net::CompletionCallback callback_;
   scoped_refptr<net::IOBuffer> buf_;
   TimeTicks start_;
   const net::NetLog::EventType end_event_type_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncCallback);
@@ skipping 1482 matching lines @@
   Trace("%s 0x%p 0x%x 0x%x", msg, reinterpret_cast<void*>(this),
         entry_.address().value(), node_.address().value());
 
   Trace("  data: 0x%x 0x%x 0x%x", entry_.Data()->data_addr[0],
         entry_.Data()->data_addr[1], entry_.Data()->long_key);
 
   Trace("  doomed: %d 0x%x", doomed_, dirty);
 }
 
 }  // namespace disk_cache