Use std::tie() for operator< in ui/

ui/gfx/geometry/point_f.h

 // 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.
 
 #ifndef UI_GFX_GEOMETRY_POINT_F_H_
 #define UI_GFX_GEOMETRY_POINT_F_H_
 
 #include <iosfwd>
 #include <string>
+#include <tuple>
 
 #include "ui/gfx/geometry/point.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 #include "ui/gfx/gfx_export.h"
 
 namespace gfx {
 
 // A floating version of gfx::Point.
 class GFX_EXPORT PointF {
  public:
@@ skipping 36 matching lines @@
 
   Vector2dF OffsetFromOrigin() const { return Vector2dF(x_, y_); }
 
   // A point is less than another point if its y-value is closer
   // to the origin. If the y-values are the same, then point with
   // the x-value closer to the origin is considered less than the
   // other.
   // This comparison is required to use PointF in sets, or sorted
   // vectors.
   bool operator<(const PointF& rhs) const {
-    return (y_ == rhs.y_) ? (x_ < rhs.x_) : (y_ < rhs.y_);
+    return std::tie(y_, x_) < std::tie(rhs.y_, rhs.x_);
   }
 
   void Scale(float scale) {
     Scale(scale, scale);
   }
 
   void Scale(float x_scale, float y_scale) {
     SetPoint(x() * x_scale, y() * y_scale);
   }
 
@@ skipping 40 matching lines @@
 }
 
 // This is declared here for use in gtest-based unit tests but is defined in
 // the gfx_test_support target. Depend on that to use this in your unit test.
 // This should not be used in production code - call ToString() instead.
 void PrintTo(const PointF& point, ::std::ostream* os);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_GEOMETRY_POINT_F_H_