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

base/stl_util.h

 // Copyright (c) 2011 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.
 
 // Derived from google3/util/gtl/stl_util.h
 
 #ifndef BASE_STL_UTIL_H_
 #define BASE_STL_UTIL_H_
 
 #include <algorithm>
@@ skipping 80 matching lines @@
 }
 
 // Counts the number of instances of val in a container.
 template <typename Container, typename T>
 typename std::iterator_traits<
     typename Container::const_iterator>::difference_type
 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.

[danakj, 2015/11/14 00:39:01]

Can you just delete this in this CL?

[davidben, 2015/11/16 21:27:38]

There's a lot more consumers. I only did a few for now just to show try bots
would go green and that nothing would explode if I switched all vector_as_array
calls to vector::data. I've kept the comment change, but reverted the rest,
since it'll all go away later.

I've filed https://crbug.com/556678 to get the rest and will remove
vector_as_array when that's sorted out.

 template<typename T>
 inline T* vector_as_array(std::vector<T>* v) {
-  return v->empty() ? NULL : &*v->begin();
+  return v->data();
 }
 
 template<typename T>
 inline const T* vector_as_array(const std::vector<T>* v) {
-  return v->empty() ? NULL : &*v->begin();
+  return v->data();
 }
 
 // Return a mutable char* pointing to a string's internal buffer,
 // which may not be null-terminated. Writing through this pointer will
 // modify the string.
 //
 // string_as_array(&str)[i] is valid for 0 <= i < str.size() until the
 // next call to a string method that invalidates iterators.
 //
 // As of 2006-04, there is no standard-blessed way of getting a
@@ skipping 144 matching lines @@
 bool STLIncludes(const Arg1& a1, const Arg2& a2) {
   DCHECK(STLIsSorted(a1));
   DCHECK(STLIsSorted(a2));
   return std::includes(a1.begin(), a1.end(),
                        a2.begin(), a2.end());
 }
 
 }  // namespace base
 
 #endif  // BASE_STL_UTIL_H_