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

ui/gfx/rect.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 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.
@@ skipping 15 matching lines @@
 #elif defined(OS_IOS)
 #include <CoreGraphics/CoreGraphics.h>
 #elif defined(OS_MACOSX)
 #include <ApplicationServices/ApplicationServices.h>
 #endif
 
 namespace gfx {
 
 class Insets;
 
-class UI_EXPORT Rect : public RectBase<Rect, Point, Size, Insets, int> {
+class UI_EXPORT Rect
+    : public RectBase<Rect, Point, Size, Insets, Vector2d, int> {
  public:
   Rect();
   Rect(int width, int height);
   Rect(int x, int y, int width, int height);
 #if defined(OS_WIN)
   explicit Rect(const RECT& r);
 #elif defined(OS_MACOSX)
   explicit Rect(const CGRect& r);
 #elif defined(TOOLKIT_GTK)
   explicit Rect(const GdkRectangle& r);
@@ skipping 22 matching lines @@
 
 inline bool operator==(const Rect& lhs, const Rect& rhs) {
   return lhs.origin() == rhs.origin() && lhs.size() == rhs.size();
 }
 
 inline bool operator!=(const Rect& lhs, const Rect& rhs) {
   return !(lhs == rhs);
 }
 
 #if !defined(COMPILER_MSVC)
-extern template class RectBase<Rect, Point, Size, Insets, int>;
+extern template class RectBase<Rect, Point, Size, Insets, Vector2d, int>;
 #endif
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RECT_H_