Fix some extern usage in .cc files.

chrome/browser/local_discovery/privet_http_impl.cc

 // 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.
 
 #include "chrome/browser/local_discovery/privet_http_impl.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/rand_util.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/utf_string_conversions.h"
 #include "base/thread_task_runner_handle.h"
 #include "chrome/browser/local_discovery/privet_constants.h"
+#include "chrome/common/cloud_print/cloud_print_constants.h"
 #include "net/base/url_util.h"
 #include "url/gurl.h"
 
 #if defined(ENABLE_PRINT_PREVIEW)
 #include "chrome/browser/local_discovery/pwg_raster_converter.h"
 #include "components/cloud_devices/common/printer_description.h"
 #include "printing/pdf_render_settings.h"
 #include "printing/pwg_raster_settings.h"
 #include "ui/gfx/text_elider.h"
 #endif  // ENABLE_PRINT_PREVIEW
 
-namespace cloud_print {
-extern const char kContentTypeJSON[];
-}
-
 namespace local_discovery {
 
 namespace {
 const char kUrlPlaceHolder[] = "http://host/";
 const char kPrivetRegisterActionArgName[] = "action";
 const char kPrivetRegisterUserArgName[] = "user";
 
 const int kPrivetCancelationTimeoutSeconds = 3;
 
 #if defined(ENABLE_PRINT_PREVIEW)
@@ skipping 750 matching lines @@
     PrivetLocalPrintOperation::Delegate* delegate) {
 #if defined(ENABLE_PRINT_PREVIEW)
   return scoped_ptr<PrivetLocalPrintOperation>(
       new PrivetLocalPrintOperationImpl(info_client(), delegate));
 #else
   return scoped_ptr<PrivetLocalPrintOperation>();
 #endif  // ENABLE_PRINT_PREVIEW
 }
 
 }  // namespace local_discovery