Move crypto_helpers from sync to base

base/rand_util.cc

Index: base/rand_util.cc
diff --git a/base/rand_util.cc b/base/rand_util.cc
index d89f8b725080d3912944b5b7bc60c19096c683ae..9d90a88e9de3db6685c0f7eb6567be40a6e4045d 100644
--- a/base/rand_util.cc
+++ b/base/rand_util.cc
@@ -41,6 +41,17 @@ uint64 RandGenerator(uint64 max) {
   return base::RandUint64() % max;
 }
 
+void RandBytes(void* output, size_t output_length) {
+  uint64 random_int;
+  const char* random_int_bytes = reinterpret_cast<const char*>(&random_int);
+  size_t random_int_size = sizeof(random_int);
+  for (size_t i = 0; i < output_length; i += random_int_size) {
+    random_int = base::RandUint64();
+    size_t copy_count = std::min(output_length - i, random_int_size);
+    memcpy(((uint8*)output) + i, random_int_bytes, copy_count);
+  }

[abarth-chromium, 2011/05/02 18:23:20]

I'd recommend re-implementing RandBytesAsString in terms of this function.  You
can use the WriteInto function from string_util to make that a one-liner.

+}
+
 std::string RandBytesAsString(size_t length) {
   const size_t kBitsPerChar = 8;
   const int kCharsPerInt64 = sizeof(uint64)/sizeof(char);