Add Vector2d classes that represent offsets, instead of using Point.

ui/gfx/vector2d.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.
+
+// Defines a simple integer vector class.  This class is used to indicate a
+// distance in two dimentions between two points. Subtracting two points should
+// produce a vector, and adding a vector to a point produces the point at the
+// vector's distance from the original point.
+
+#ifndef UI_GFX_VECTOR2D_H_
+#define UI_GFX_VECTOR2D_H_
+
+#include <string>
+
+#include "ui/base/ui_export.h"
+#include "ui/gfx/vector2d_f.h"
+
+namespace gfx {
+
+class UI_EXPORT Vector2d {
+ public:
+  Vector2d();
+  Vector2d(int x, int y);
+
+  int x() const { return m_x; }
+  void set_x(int x) { m_x = x; }
+
+  int y() const { return m_y; }
+  void set_y(int y) { m_y = y; }
+
+  void Grow(int x, int y) {
+    m_x += x;
+    m_y += y;
+  }
+
+  void Add(const Vector2d& other) {
+    m_x += other.m_x;
+    m_y += other.m_y;
+  }
+
+  std::string ToString() const;
+
+  operator Vector2dF() const { return Vector2dF(m_x, m_y); }
+
+ private:
+  int m_x;

[tfarina, 2012/10/25 00:40:20]

nit: please remember that we are in chromium code, not WebKit land :)

s/m_x/x_

[danakj, 2012/10/25 00:59:09]

oh, shoot. thanks.

+  int m_y;
+};
+
+inline Vector2d operator-(const Vector2d& v) {
+  return Vector2d(-v.x(), -v.y());
+}
+
+}  // namespace gfx
+
+#endif // UI_GFX_VECTOR2D_H_