Make vector_as_array use std::vector::data and switch a few directories.

base/stl_util.h

Index: base/stl_util.h
diff --git a/base/stl_util.h b/base/stl_util.h
index e937d2f3ed9157d433cc62fb71958bd9c71cd6d9..848ef777bc7df63ae2e6e42beb07cfdacb4e4c20 100644
--- a/base/stl_util.h
+++ b/base/stl_util.h
@@ -98,9 +98,7 @@ STLCount(const Container& container, const T& val) {
   return std::count(container.begin(), container.end(), val);
 }
 
-// To treat a possibly-empty vector as an array, use these functions.
-// If you know the array will never be empty, you can use &*v.begin()
-// directly, but that is undefined behaviour if |v| is empty.
+// Deprecated: Use v.data() instead.
 template<typename T>
 inline T* vector_as_array(std::vector<T>* v) {
   return v->empty() ? NULL : &*v->begin();