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

ui/gfx/rect_base.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.
 
 // A template for a simple rectangle class.  The containment semantics
 // are array-like; that is, the coordinate (x, y) is considered to be
 // contained by the rectangle, but the coordinate (x + width, y) is not.
 // The class will happily let you create malformed rectangles (that is,
 // rectangles with negative width and/or height), but there will be assertions
 // in the operations (such as Contains()) to complain in this case.
 
 #ifndef UI_GFX_RECT_BASE_H_
 #define UI_GFX_RECT_BASE_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 
 namespace gfx {
 
 template<typename Class,
          typename PointClass,
          typename SizeClass,
          typename InsetsClass,
+         typename VectorClass,
          typename Type>
 class UI_EXPORT RectBase {
  public:
   Type x() const { return origin_.x(); }
   void set_x(Type x) { origin_.set_x(x); }
 
   Type y() const { return origin_.y(); }
   void set_y(Type y) { origin_.set_y(y); }
 
   Type width() const { return size_.width(); }
   void set_width(Type width) { size_.set_width(width); }
 
   Type height() const { return size_.height(); }
   void set_height(Type height) { size_.set_height(height); }
 
   const PointClass& origin() const { return origin_; }
   void set_origin(const PointClass& origin) { origin_ = origin; }
 
   const SizeClass& size() const { return size_; }
   void set_size(const SizeClass& size) { size_ = size; }
 
   Type right() const { return x() + width(); }
   Type bottom() const { return y() + height(); }
 
+  VectorClass OffsetFromOrigin() const {
+    return VectorClass(x(), y());
+  }
+
   void SetRect(Type x, Type y, Type width, Type height);
 
   // Shrink the rectangle by a horizontal and vertical distance on all sides.
   void Inset(Type horizontal, Type vertical) {
     Inset(horizontal, vertical, horizontal, vertical);
   }
 
   // Shrink the rectangle by the given insets.
   void Inset(const InsetsClass& insets);
 
   // Shrink the rectangle by the specified amount on each side.
   void Inset(Type left, Type top, Type right, Type bottom);
 
   // Move the rectangle by a horizontal and vertical distance.
   void Offset(Type horizontal, Type vertical);
-  void Offset(const PointClass& point) {
-    Offset(point.x(), point.y());
+  void Offset(const VectorClass& distance) {
+    Offset(distance.x(), distance.y());
   }
 
   InsetsClass InsetsFrom(const Class& inner) const {
     return InsetsClass(inner.y() - y(),
                        inner.x() - x(),
                        bottom() - inner.bottom(),
                        right() - inner.right());
   }
 
   // Returns true if the area of the rectangle is zero.
@@ skipping 66 matching lines @@
   ~RectBase();
 
  private:
   PointClass origin_;
   SizeClass size_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RECT_BASE_H_