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

ui/gfx/vector2d.cc

 // 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.
 
-#include "ui/gfx/insets_f.h"
-
 #include "base/stringprintf.h"
+#include "ui/gfx/vector2d.h"
 
 namespace gfx {
 
-std::string InsetsF::ToString() const {
-  // Print members in the same order of the constructor parameters.
-  return StringPrintf("%f,%f,%f,%f", top_,  left_, bottom_, right_);
+Vector2d::Vector2d()
+    : m_x(0),
+      m_y(0) {
+}
+
+Vector2d::Vector2d(int x, int y)
+    : m_x(x),
+      m_y(y) {
+}
+
+std::string Vector2d::ToString() const {
+  return base::StringPrintf("[%d %d]", m_x, m_y);
 }
 
 }  // namespace gfx