Add other variations (with ids) for NTPSnippets to chrome://flags

components/variations/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_VARIATIONS_HTTP_HEADER_PROVIDER_H_
 #define COMPONENTS_VARIATIONS_VARIATIONS_HTTP_HEADER_PROVIDER_H_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 23 matching lines @@
   // Returns the value of the client data header, computing and caching it if
   // necessary.
   std::string GetClientDataHeader();
 
   // Returns a space-separated string containing the list of current active
   // variations (as would be reported in the |variation_id| repeated field of
   // the ClientVariations proto). The returned string is guaranteed to have a
   // a leading and trailing space, e.g. " 123 234 345 ".
   std::string GetVariationsString();
 
+  // Forces the list of |variation_ids| (which will be modified by adding the
+  // comma-separated |command_line_variation_ids|). This is a wrapper function
+  // around SetDefaultVariationIds.
+  bool ForceVariationIds(
+      const std::string& command_line_variation_ids,
+      std::vector<std::string>* variation_ids);
+
   // 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);
+  // the X-Client-Data request header. This is intended for development use to
+  // force a server side experiment id. |variation_ids| should be a list of
+  // strings of numeric experiment ids. If an id is prefixed with "t" it will
+  // be treated as a trigger experiment id.
+  bool SetDefaultVariationIds(const std::vector<std::string>& variation_ids);
 
   // Resets any cached state for tests.
   void ResetForTesting();
 
  private:
   friend struct base::DefaultSingletonTraits<VariationsHttpHeaderProvider>;
 
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
                            SetDefaultVariationIds_Valid);
   FRIEND_TEST_ALL_PREFIXES(VariationsHttpHeaderProviderTest,
@@ skipping 50 matching lines @@
   std::set<VariationID> synthetic_variation_ids_set_;
 
   std::string variation_ids_header_;
 
   DISALLOW_COPY_AND_ASSIGN(VariationsHttpHeaderProvider);
 };
 
 }  // namespace variations
 
 #endif  // COMPONENTS_VARIATIONS_VARIATIONS_HTTP_HEADER_PROVIDER_H_