Modify rappor parameters.

components/rappor/rappor_parameters.h

Index: components/rappor/rappor_parameters.h
diff --git a/components/rappor/rappor_parameters.h b/components/rappor/rappor_parameters.h
index 77b16146f608cde86001c8af669d1edf03e7979e..ca625ba4d8e3216969d5efe2b545aabb91878029 100644
--- a/components/rappor/rappor_parameters.h
+++ b/components/rappor/rappor_parameters.h
@@ -12,6 +12,7 @@ namespace rappor {
 enum Probability {
   PROBABILITY_75,    // 75%
   PROBABILITY_50,    // 50%
+  PROBABILITY_25,    // 25%
 };
 
 // An object describing a rappor metric and the parameters used to generate it.
@@ -22,6 +23,12 @@ struct RapporParameters {
   // Get a string representing the parameters, for DCHECK_EQ.
   std::string ToString() const;
 
+  // The maximum number of cohorts we divide clients into.
+  static const int kMaxCohorts;
+
+  // The number of cohorts to divide the reports for this metric into.
+  int num_cohorts;
+
   // The number of bytes stored in the Bloom filter.
   int bloom_filter_size_bytes;
   // The number of hash functions used in the Bloom filter.