Make the copy of GURL in src/url buildable as a component build. (try 2)

url/url_canon_icu.h

 // Copyright 2013 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 URL_URL_CANON_ICU_H_
 #define URL_URL_CANON_ICU_H_
 
 // ICU integration functions.
 
 #include "url/url_canon.h"
+#include "url/url_export.h"
 
 typedef struct UConverter UConverter;
 
 namespace url_canon {
 
 // An implementation of CharsetConverter that implementations can use to
 // interface the canonicalizer with ICU's conversion routines.
-class ICUCharsetConverter : public CharsetConverter {
+class URL_EXPORT ICUCharsetConverter : public CharsetConverter {
  public:
   // Constructs a converter using an already-existing ICU character set
   // converter. This converter is NOT owned by this object; the lifetime must
   // be managed by the creator such that it is alive as long as this is.
   ICUCharsetConverter(UConverter* converter);
 
   virtual ~ICUCharsetConverter();
 
   virtual void ConvertFromUTF16(const char16* input,
                                 int input_len,
                                 CanonOutput* output);
 
  private:
   // The ICU converter, not owned by this class.
   UConverter* converter_;
 };
 
 }  // namespace url_canon
 
 #endif  // URL_URL_CANON_ICU_H_