[Sync] Add histograms for cookie jar state on Sessions commit

sync/engine/commit_processor.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 SYNC_ENGINE_COMMIT_PROCESSOR_H_
 #define SYNC_ENGINE_COMMIT_PROCESSOR_H_
 
 #include <stddef.h>
 
 #include <map>
@@ skipping 27 matching lines @@
   // The CommitProcessor does not own this map.
   explicit CommitProcessor(CommitContributorMap* commit_contributor_map);
   ~CommitProcessor();
 
   // Gathers a set of contributions to be used to populate a commit message.
   //
   // For each of the |commit_types| in this CommitProcessor's CommitContributor
   // map, gather any entries queued for commit into CommitContributions.  The
   // total number of entries in all the returned CommitContributions shall not
   // exceed |max_entries|.
+  // Note: |cookie_jar_mismatch| and |cookie_jar_empty| are used only for
+  // metrics recording purposes specific to the SESSIONS type.
   void GatherCommitContributions(ModelTypeSet commit_types,
                                  size_t max_entries,
+                                 bool cookie_jar_mismatch,
+                                 bool cookie_jar_empty,
                                  Commit::ContributionMap* contributions);
 
  private:
   // A map of 'commit contributors', one for each enabled type.
   CommitContributorMap* commit_contributor_map_;
 
   DISALLOW_COPY_AND_ASSIGN(CommitProcessor);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_ENGINE_COMMIT_PROCESSOR_H_