Randomly select a single rappor sample when more than one is collected.

components/rappor/bloom_filter.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_RAPPOR_BLOOM_FILTER_H_
 #define COMPONENTS_RAPPOR_BLOOM_FILTER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/macros.h"
 #include "components/rappor/byte_vector_utils.h"
 
 namespace rappor {
 
 // BloomFilter is a simple Bloom filter for keeping track of a set of strings.
 class BloomFilter {
  public:
   // Constructs a BloomFilter using |bytes_size| bytes of Bloom filter bits,
   // and |hash_function_count| hash functions to set bits in the filter. The
   // hash functions will be generated by using seeds in the range
   // |hash_seed_offset| to (|hash_seed_offset| + |hash_function_count|).
   BloomFilter(uint32_t bytes_size,
               uint32_t hash_function_count,
               uint32_t hash_seed_offset);
   ~BloomFilter();
 
-  // Add a single string to the Bloom filter.
-  void AddString(const std::string& str);
+  // Sets the Bloom filter bits to contain a single string.
+  void SetString(const std::string& str);
 
   // Returns the current value of the Bloom filter's bit array.
   const ByteVector& bytes() const { return bytes_; };
 
+  // Sets bytes for testing purposes.
+  void SetBytesForTesting(const ByteVector& bytes);
+
  private:
   // Stores the byte array of the Bloom filter.
   ByteVector bytes_;
 
   // The number of bits to set for each string added.
   uint32_t hash_function_count_;
 
   // A number add to a hash function index to get a seed for that hash function.
   uint32_t hash_seed_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(BloomFilter);
 };
 
 }  // namespace rappor
 
 #endif  // COMPONENTS_RAPPOR_BLOOM_FILTER_H_