Modify rappor parameters.

components/rappor/byte_vector_utils.cc

Index: components/rappor/byte_vector_utils.cc
diff --git a/components/rappor/byte_vector_utils.cc b/components/rappor/byte_vector_utils.cc
index 57f25744566d19056f3b1cd511789f467a773e2a..23d925c2e31af126d4498f7d9b5be14445f4f6cc 100644
--- a/components/rappor/byte_vector_utils.cc
+++ b/components/rappor/byte_vector_utils.cc
@@ -78,6 +78,14 @@ bool HMAC_DRBG_Update(const std::string& provided_data,
 
 }  // namespace
 
+ByteVector* ByteVectorAnd(const ByteVector& lhs, ByteVector* rhs) {
+  DCHECK_EQ(lhs.size(), rhs->size());
+  for (size_t i = 0, len = lhs.size(); i < len; ++i) {

[Alexei Svitkine (slow), 2014/05/20 06:59:49]

Nit: Remove len and just do i < lhs.size(). (Compiler should be inlining
lhs.size() in already.)

[Steven Holte, 2014/05/20 22:53:53]

Done.

+    (*rhs)[i] = lhs[i] & (*rhs)[i];
+  }
+  return rhs;
+}
+
 ByteVector* ByteVectorOr(const ByteVector& lhs, ByteVector* rhs) {
   DCHECK_EQ(lhs.size(), rhs->size());
   for (size_t i = 0, len = lhs.size(); i < len; ++i) {
@@ -127,6 +135,8 @@ ByteVector ByteVectorGenerator::GetWeightedRandomByteVector(
       return *ByteVectorOr(GetRandomByteVector(), &bytes);
     case PROBABILITY_50:
       return bytes;
+    case PROBABILITY_25:
+      return *ByteVectorAnd(GetRandomByteVector(), &bytes);
   }
   NOTREACHED();
   return bytes;