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

ui/gfx/geometry/cubic_bezier.cc

 // 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.
 
 #include "ui/gfx/geometry/cubic_bezier.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/logging.h"
 
 namespace gfx {
 
 static const double kBezierEpsilon = 1e-7;
 
 CubicBezier::CubicBezier(double p1x, double p1y, double p2x, double p2y) {
   InitCoefficients(p1x, p1y, p2x, p2y);
   InitGradients(p1x, p1y, p2x, p2y);
   InitRange(p1y, p2y);
 }
 
+CubicBezier::CubicBezier(const CubicBezier& other) = default;
+
 void CubicBezier::InitCoefficients(double p1x,
                                    double p1y,
                                    double p2x,
                                    double p2y) {
   // Calculate the polynomial coefficients, implicit first and last control
   // points are (0,0) and (1,1).
   cx_ = 3.0 * p1x;
   bx_ = 3.0 * (p2x - p1x) - cx_;
   ax_ = 1.0 - cx_ - bx_;
 
@@ skipping 140 matching lines @@
   double dx = SampleCurveDerivativeX(t);
   double dy = SampleCurveDerivativeY(t);
   return dy / dx;
 }
 
 double CubicBezier::Slope(double x) const {
   return SlopeWithEpsilon(x, kBezierEpsilon);
 }
 
 }  // namespace gfx