Make adding and subtracting gfx:: point types simpler.

ui/gfx/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_POINT_F_H_
 #define UI_GFX_POINT_F_H_
 
 #include <string>
 
 #include "ui/base/ui_export.h"
 #include "ui/gfx/point_base.h"
 
 namespace gfx {
-class Point;
 
 // A floating version of gfx::Point.
 class UI_EXPORT PointF : public PointBase<PointF, float> {
  public:
   PointF();
   PointF(float x, float y);
-  explicit PointF(Point& point);
-  ~PointF() {}
-
-  Point ToPoint() const;
+  PointF(const PointF& other);

[sky, 2012/09/28 23:05:49]

Why remove the explicit?

+  ~PointF();
 
   // Returns a string representation of point.
   std::string ToString() const;
 };
 
+inline PointF operator+(PointF lhs, PointF rhs) {
+  return lhs.Add(rhs);
+}
+
+inline PointF operator-(PointF lhs, PointF rhs) {
+  return lhs.Subtract(rhs);
+}
+
 #if !defined(COMPILER_MSVC)
 extern template class PointBase<PointF, float>;
 #endif
 
 }  // namespace gfx
 
 #endif  // UI_GFX_POINT_F_H_