AU: Manual proxy support

proxy_resolver.h

 // Copyright (c) 2010 The Chromium OS 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 CHROMEOS_PLATFORM_UPDATE_ENGINE_PROXY_RESOLVER_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_PROXY_RESOLVER_H__
 
 #include <base/logging.h>
 
 #include <string>
@@ skipping 17 matching lines @@
   virtual bool GetProxiesForUrl(const std::string& url,
                                 std::vector<std::string>* out_proxies) = 0;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ProxyResolver);
 };
 
 // Always says to not use a proxy
 class DirectProxyResolver : public ProxyResolver {
  public:
+  DirectProxyResolver() {}
   virtual bool GetProxiesForUrl(const std::string& url,
                                 std::vector<std::string>* out_proxies);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DirectProxyResolver);
 };
 
 }  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_PROXY_RESOLVER_H__