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

ui/gfx/size.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_SIZE_H_
 #define UI_GFX_SIZE_H_
 
 #include <string>
 
 #include "build/build_config.h"
 #include "ui/base/ui_export.h"
 #include "ui/gfx/size_base.h"
 #include "ui/gfx/size_f.h"
+#include "ui/gfx/vector2d.h"
 
 #if defined(OS_WIN)
 typedef struct tagSIZE SIZE;
 #elif defined(OS_IOS)
 #include <CoreGraphics/CoreGraphics.h>
 #elif defined(OS_MACOSX)
 #include <ApplicationServices/ApplicationServices.h>
 #endif
 
 namespace gfx {
@@ skipping 35 matching lines @@
 };
 
 inline bool operator==(const Size& lhs, const Size& rhs) {
   return lhs.width() == rhs.width() && lhs.height() == rhs.height();
 }
 
 inline bool operator!=(const Size& lhs, const Size& rhs) {
   return !(lhs == rhs);
 }
 
+inline Size SizeOfVector2d(const Vector2d& v) {
+  return Size(std::abs(v.x()), std::abs(v.y()));
+}
+
 #if !defined(COMPILER_MSVC)
 extern template class SizeBase<Size, int>;
 #endif
 
 }  // namespace gfx
 
 #endif  // UI_GFX_SIZE_H_