Add Chromium's ScopedVector.

Trivial changes from the original excepting scoped_vector_unittest.cc,
diff here: https://paste.googleplex.com/6664017300946944

This is a prerequisite for:
http://review.webrtc.org/9919004/

TBR=henrike@webrtc.org
BUG=2894

Review URL: https://webrtc-codereview.appspot.com/12179004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5938 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/system_wrappers/interface/scoped_vector.h b/webrtc/system_wrappers/interface/scoped_vector.h
new file mode 100644
index 0000000..68db3a1
--- /dev/null
+++ b/webrtc/system_wrappers/interface/scoped_vector.h
@@ -0,0 +1,149 @@
+/*
+ *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+// Borrowed from Chromium's src/base/memory/scoped_vector.h.
+
+#ifndef WEBRTC_SYSTEM_WRAPPERS_INTERFACE_SCOPED_VECTOR_H_
+#define WEBRTC_SYSTEM_WRAPPERS_INTERFACE_SCOPED_VECTOR_H_
+
+#include <assert.h>
+#include <algorithm>
+#include <vector>
+
+#include "webrtc/system_wrappers/interface/stl_util.h"
+#include "webrtc/system_wrappers/source/move.h"
+
+namespace webrtc {
+
+// ScopedVector wraps a vector deleting the elements from its
+// destructor.
+template <class T>
+class ScopedVector {
+  WEBRTC_MOVE_ONLY_TYPE_FOR_CPP_03(ScopedVector, RValue)
+
+ public:
+  typedef typename std::vector<T*>::allocator_type allocator_type;
+  typedef typename std::vector<T*>::size_type size_type;
+  typedef typename std::vector<T*>::difference_type difference_type;
+  typedef typename std::vector<T*>::pointer pointer;
+  typedef typename std::vector<T*>::const_pointer const_pointer;
+  typedef typename std::vector<T*>::reference reference;
+  typedef typename std::vector<T*>::const_reference const_reference;
+  typedef typename std::vector<T*>::value_type value_type;
+  typedef typename std::vector<T*>::iterator iterator;
+  typedef typename std::vector<T*>::const_iterator const_iterator;
+  typedef typename std::vector<T*>::reverse_iterator reverse_iterator;
+  typedef typename std::vector<T*>::const_reverse_iterator
+      const_reverse_iterator;
+
+  ScopedVector() {}
+  ~ScopedVector() { clear(); }
+  ScopedVector(RValue other) { swap(*other.object); }
+
+  ScopedVector& operator=(RValue rhs) {
+    swap(*rhs.object);
+    return *this;
+  }
+
+  reference operator[](size_t index) { return v_[index]; }
+  const_reference operator[](size_t index) const { return v_[index]; }
+
+  bool empty() const { return v_.empty(); }
+  size_t size() const { return v_.size(); }
+
+  reverse_iterator rbegin() { return v_.rbegin(); }
+  const_reverse_iterator rbegin() const { return v_.rbegin(); }
+  reverse_iterator rend() { return v_.rend(); }
+  const_reverse_iterator rend() const { return v_.rend(); }
+
+  iterator begin() { return v_.begin(); }
+  const_iterator begin() const { return v_.begin(); }
+  iterator end() { return v_.end(); }
+  const_iterator end() const { return v_.end(); }
+
+  const_reference front() const { return v_.front(); }
+  reference front() { return v_.front(); }
+  const_reference back() const { return v_.back(); }
+  reference back() { return v_.back(); }
+
+  void push_back(T* elem) { v_.push_back(elem); }
+
+  void pop_back() {
+    assert(!empty());
+    delete v_.back();
+    v_.pop_back();
+  }
+
+  std::vector<T*>& get() { return v_; }
+  const std::vector<T*>& get() const { return v_; }
+  void swap(std::vector<T*>& other) { v_.swap(other); }
+  void swap(ScopedVector<T>& other) { v_.swap(other.v_); }
+  void release(std::vector<T*>* out) {
+    out->swap(v_);
+    v_.clear();
+  }
+
+  void reserve(size_t capacity) { v_.reserve(capacity); }
+
+  // Resize, deleting elements in the disappearing range if we are shrinking.
+  void resize(size_t new_size) {
+    if (v_.size() > new_size)
+      STLDeleteContainerPointers(v_.begin() + new_size, v_.end());
+    v_.resize(new_size);
+  }
+
+  template<typename InputIterator>
+  void assign(InputIterator begin, InputIterator end) {
+    v_.assign(begin, end);
+  }
+
+  void clear() { STLDeleteElements(&v_); }
+
+  // Like |clear()|, but doesn't delete any elements.
+  void weak_clear() { v_.clear(); }
+
+  // Lets the ScopedVector take ownership of |x|.
+  iterator insert(iterator position, T* x) {
+    return v_.insert(position, x);
+  }
+
+  // Lets the ScopedVector take ownership of elements in [first,last).
+  template<typename InputIterator>
+  void insert(iterator position, InputIterator first, InputIterator last) {
+    v_.insert(position, first, last);
+  }
+
+  iterator erase(iterator position) {
+    delete *position;
+    return v_.erase(position);
+  }
+
+  iterator erase(iterator first, iterator last) {
+    STLDeleteContainerPointers(first, last);
+    return v_.erase(first, last);
+  }
+
+  // Like |erase()|, but doesn't delete the element at |position|.
+  iterator weak_erase(iterator position) {
+    return v_.erase(position);
+  }
+
+  // Like |erase()|, but doesn't delete the elements in [first, last).
+  iterator weak_erase(iterator first, iterator last) {
+    return v_.erase(first, last);
+  }
+
+ private:
+  std::vector<T*> v_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_SYSTEM_WRAPPERS_INTERFACE_SCOPED_VECTOR_H_