ui: Prefer +/- operators to apply offsets.

ui/gfx/vector2d_f.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/vector2d_f.h"
 
 #include <cmath>
 
 #include "base/stringprintf.h"
 
@@ skipping 43 matching lines @@
 double CrossProduct(const Vector2dF& lhs, const Vector2dF& rhs) {
   return static_cast<double>(lhs.x()) * rhs.y() -
       static_cast<double>(lhs.y()) * rhs.x();
 }
 
 double DotProduct(const Vector2dF& lhs, const Vector2dF& rhs) {
   return static_cast<double>(lhs.x()) * rhs.x() +
       static_cast<double>(lhs.y()) * rhs.y();
 }
 
+Vector2dF ScaleVector2d(const Vector2dF& v, float x_scale, float y_scale) {
+  Vector2dF scaled_v(v);
+  scaled_v.Scale(x_scale, y_scale);
+  return scaled_v;
+}
+
 }  // namespace gfx