Add IPC fuzzer GenerateTraits for some cc types.

tools/ipc_fuzzer/mutate/rand_util.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 TOOLS_IPC_FUZZER_MUTATE_RAND_UTIL_H_
 #define TOOLS_IPC_FUZZER_MUTATE_RAND_UTIL_H_
 
 #include "base/basictypes.h"
 #include "third_party/mt19937ar/mt19937ar.h"
 
@@ skipping 17 matching lines @@
 }
 
 inline uint32 RandInRange(uint32 range) {
   return RandU32() % range;
 }
 
 inline bool RandEvent(uint32 frequency) {
   return RandInRange(frequency) == 0;
 }
 
+inline size_t RandElementCount() {
+  return RandU32() % 10;
+}
+
 }  // namespace ipc_fuzzer
 
 #endif  // TOOLS_IPC_FUZZER_MUTATE_RAND_UTIL_H_