Update comments in rand_util.h.

base/rand_util.h

Index: base/rand_util.h
diff --git a/base/rand_util.h b/base/rand_util.h
index 82e548b82923d45d0c805be920981528e0c60887..39e2f104c43cc61c64eb0ef397ba67d559feef71 100644
--- a/base/rand_util.h
+++ b/base/rand_util.h
@@ -13,20 +13,23 @@
 
 namespace base {
 
-// Returns a random number in range [0, kuint64max]. Thread-safe.
+// The random number generator functions below generate
+// cryptographically secure random numbers. They are thread-safe.
+
+// Random integer in range [0, kuint64max].
 BASE_EXPORT uint64 RandUint64();
 
-// Returns a random number between min and max (inclusive). Thread-safe.
+// Random integer in range [min, max).
 BASE_EXPORT int RandInt(int min, int max);
 
-// Returns a random number in range [0, range).  Thread-safe.
+// Random integer in range [0, range).
 //
 // Note that this can be used as an adapter for std::random_shuffle():
 // Given a pre-populated |std::vector<int> myvector|, shuffle it as
 //   std::random_shuffle(myvector.begin(), myvector.end(), base::RandGenerator);
 BASE_EXPORT uint64 RandGenerator(uint64 range);
 
-// Returns a random double in range [0, 1). Thread-safe.

[Ryan Sleevi, 2012/06/04 17:46:30]

I feel like these comments were correct as originally written, in line with
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml?showone=Functi...

+// Random double in range [0, 1).
 BASE_EXPORT double RandDouble();
 
 // Given input |bits|, convert with maximum precision to a double in