Add defaulted move constructors for some types that just got copy constructors

webrtc/modules/desktop_capture/desktop_region.cc

 /*
  *  Copyright (c) 2013 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.
  */
 
 #include "webrtc/modules/desktop_capture/desktop_region.h"
 
 #include <assert.h>
 
 #include <algorithm>
 
 namespace webrtc {
 
 DesktopRegion::RowSpan::RowSpan(int32_t left, int32_t right)
     : left(left), right(right) {
 }
 
 DesktopRegion::Row::Row(const Row&) = default;
+DesktopRegion::Row::Row(Row&&) = default;
 
 DesktopRegion::Row::Row(int32_t top, int32_t bottom)
     : top(top), bottom(bottom) {
 }
 
 DesktopRegion::Row::~Row() {}
 
 DesktopRegion::DesktopRegion() {}
 
 DesktopRegion::DesktopRegion(const DesktopRect& rect) {
@@ skipping 528 matching lines @@
     previous = bottom_row;
     ++bottom_row;
   } while (bottom_row != region_.rows_.end() &&
            previous->second->bottom == bottom_row->second->top &&
            IsSpanInRow(*bottom_row->second, *row_span_));
   rect_ = DesktopRect::MakeLTRB(row_span_->left, row_->second->top,
                                 row_span_->right, bottom);
 }
 
 }  // namespace webrtc