Fix a bunch of clang warnings/errors.

chrome/common/net/gaia/google_service_auth_error.h

 // Copyright (c) 2009 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.
 
 // A GoogleServiceAuthError is immutable, plain old data representing an
 // error from an attempt to authenticate with a Google service.
 // It could be from Google Accounts itself, or any service using Google
 // Accounts (e.g expired credentials).  It may contain additional data such as
 // captcha challenges.
 
@@ skipping 107 matching lines @@
   // (avoids err_ = GoogleServiceAuthError(GoogleServiceAuthError::NONE), due
   // to explicit class and State enum relation. Note: shouldn't be inlined!
   static const GoogleServiceAuthError None() {
     static const GoogleServiceAuthError e(NONE);
     return e;
   }
 
   // The error information.
   const State& state() const { return state_; }
   const Captcha& captcha() const { return captcha_; }
-  const int network_error() const {
+  int network_error() const {
     return network_error_;
   }
 
  private:
   GoogleServiceAuthError(State s, int error)
       : state_(s),
         captcha_("", GURL(), GURL()),
         network_error_(error) {
   }
 
   GoogleServiceAuthError(State s, const std::string& captcha_token,
                          const GURL& captcha_image_url,
                          const GURL& captcha_unlock_url)
       : state_(s),
         captcha_(captcha_token, captcha_image_url, captcha_unlock_url),
         network_error_(0) {
   }
 
   State state_;
   Captcha captcha_;
   int network_error_;
 };
 
 #endif  // CHROME_COMMON_NET_GAIA_GOOGLE_SERVICE_AUTH_ERROR_H_