[ServiceWorker] Don't send the UMA related headers to the ServiceWorker.

components/variations/net/variations_http_header_provider.h

 // Copyright 2014 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 COMPONENTS_VARIATIONS_NET_VARIATIONS_HTTP_HEADER_PROVIDER_H_
 #define COMPONENTS_VARIATIONS_NET_VARIATIONS_HTTP_HEADER_PROVIDER_H_
 
 #include <set>
 #include <string>
 
@@ skipping 33 matching lines @@
                      bool uma_enabled,
                      net::HttpRequestHeaders* headers);
 
   // Sets *additional* variation ids and trigger variation ids to be encoded in
   // the X-Client-Data request header.  This is intended for development use to
   // force a server side experiment id.  |variation_ids| should be a
   // comma-separated string of numeric experiment ids.  If an id is prefixed
   // with "t" it will be treated as a trigger experiment id.
   bool SetDefaultVariationIds(const std::string& variation_ids);
 
+  // Returns the HTTP header names which are added in this class.
+  std::set<std::string> GetVariationHeaderNames() const;
+
  private:
   friend struct DefaultSingletonTraits<VariationsHttpHeaderProvider>;
 
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            ShouldAppendHeaders);
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            SetDefaultVariationIds_Valid);
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            SetDefaultVariationIds_Invalid);
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
@@ skipping 39 matching lines @@
   std::set<VariationID> default_trigger_id_set_;
 
   std::string variation_ids_header_;
 
   DISALLOW_COPY_AND_ASSIGN(VariationsHttpHeaderProvider);
 };
 
 }  // namespace variations
 
 #endif  // COMPONENTS_VARIATIONS_NET_VARIATIONS_HTTP_HEADER_PROVIDER_H_