Fix missing HEADLESS_EXPORT defines

headless/public/util/url_fetcher.h

 // Copyright 2016 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 HEADLESS_PUBLIC_UTIL_URL_FETCHER_H_
 #define HEADLESS_PUBLIC_UTIL_URL_FETCHER_H_
 
 #include <stddef.h>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "headless/public/headless_export.h"
 #include "net/base/net_errors.h"
 #include "url/gurl.h"
 
 namespace net {
 class HttpRequestHeaders;
 class HttpResponseHeaders;
 }  // namespace net
 
 namespace headless {
 
 // An interface for fetching URLs. Note these are only intended to be used once.
-class URLFetcher {
+class HEADLESS_EXPORT URLFetcher {
  public:
   URLFetcher() {}
   virtual ~URLFetcher() {}
 
   // Interface for reporting the fetch result.
-  class ResultListener {
+  class HEADLESS_EXPORT ResultListener {
    public:
     ResultListener() {}
 
     // Informs the listener that the fetch failed.
     virtual void OnFetchStartError(net::Error error) = 0;
 
     // Informs the listener that the fetch succeeded and returns the HTTP
     // headers and the body.  NOTE |body| must be owned by the caller and remain
     // valid until the fetcher is destroyed,
     virtual void OnFetchComplete(
@@ skipping 29 matching lines @@
                           const net::HttpRequestHeaders& request_headers,
                           ResultListener* result_listener);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(URLFetcher);
 };
 
 }  // namespace headless
 
 #endif  // HEADLESS_PUBLIC_UTIL_URL_FETCHER_H_