ui: Add out-of-line copy ctors for complex classes.

ui/gfx/render_text_mac.mm

 // Copyright (c) 2012 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.
 
 #include "ui/gfx/render_text_mac.h"
 
 #import <AppKit/AppKit.h>
 #include <ApplicationServices/ApplicationServices.h>
 #include <CoreText/CoreText.h>
 
@@ skipping 219 matching lines @@
 
 RenderTextMac::TextRun::TextRun()
     : ct_run(NULL),
       origin(SkPoint::Make(0, 0)),
       width(0),
       foreground(SK_ColorBLACK),
       underline(false),
       strike(false),
       diagonal_strike(false) {}
 
+RenderTextMac::TextRun::TextRun(const TextRun& other) = default;
+
 RenderTextMac::TextRun::~TextRun() {}
 
 float RenderTextMac::GetLayoutTextWidth() {
   base::ScopedCFTypeRef<CFMutableArrayRef> attributes_owner;
   base::ScopedCFTypeRef<CTLineRef> line(
       EnsureLayoutInternal(layout_text(), &attributes_owner));
   SkScalar baseline;
   return GetCTLineSize(line.get(), &baseline).width();
 }
 
@@ skipping 183 matching lines @@
 }
 
 void RenderTextMac::InvalidateStyle() {
   line_.reset();
   attributes_.reset();
   runs_.clear();
   runs_valid_ = false;
 }
 
 }  // namespace gfx