Add upstream code as of Chromium r334380.

Copy the unchanged source from
https://chromium.googlesource.com/chromium/src/base/ as of
r334380 (really r334285 a.k.a. 23911a0c in the base/
subtree).

Also add MODULE_LICENSE_BSD and copy Chromium's current
LICENSE file to NOTICE.

Bug: 22317122
Change-Id: I89863bfeca67b3a1ff05e6078f2f9ee4e31c5c99

1 files changed, 50 insertions, 0 deletions

diff --git a/base/containers/adapters.h b/base/containers/adapters.h
new file mode 100644
index 0000000000..cc151fc246
--- /dev/null
+++ b/base/containers/adapters.h
@@ -0,0 +1,50 @@
+// 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 BASE_CONTAINERS_ADAPTERS_H_
+#define BASE_CONTAINERS_ADAPTERS_H_
+
+#include "base/macros.h"
+
+namespace base {
+
+namespace internal {
+
+// Internal adapter class for implementing base::Reversed.
+template <typename T>
+class ReversedAdapter {
+ public:
+  typedef decltype(static_cast<T*>(nullptr)->rbegin()) Iterator;
+
+  explicit ReversedAdapter(T& t) : t_(t) {}
+  ReversedAdapter(const ReversedAdapter& ra) : t_(ra.t_) {}
+
+  Iterator begin() const { return t_.rbegin(); }
+  Iterator end() const { return t_.rend(); }
+
+ private:
+  T& t_;
+
+  DISALLOW_ASSIGN(ReversedAdapter);
+};
+
+}  // namespace internal
+
+// Reversed returns a container adapter usable in a range-based "for" statement
+// for iterating a reversible container in reverse order.
+//
+// Example:
+//
+//   std::vector<int> v = ...;
+//   for (int i : base::Reversed(v)) {
+//     // iterates through v from back to front
+//   }
+template <typename T>
+internal::ReversedAdapter<T> Reversed(T& t) {
+  return internal::ReversedAdapter<T>(t);
+}
+
+}  // namespace base
+
+#endif  // BASE_CONTAINERS_ADAPTERS_H_