ui: Add the gfx::Vector3dF class.

ui/gfx/point3_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/point3_f.h"
+
+#include "base/stringprintf.h"
+
+namespace gfx {
+
+std::string Point3F::ToString() const {
+  return base::StringPrintf("%f,%f,%f", x_, y_, z_);
+}
+
+Point3F operator+(const Point3F& lhs, const Vector3dF& rhs) {
+  float x = lhs.x() + rhs.x();
+  float y = lhs.y() + rhs.y();
+  float z = lhs.z() + rhs.z();
+  return Point3F(x, y, z);
+}
+
+// Subtract a vector from a point, producing a new point offset by the vector's
+// inverse.
+Point3F operator-(const Point3F& lhs, const Vector3dF& rhs) {
+  float x = lhs.x() - rhs.x();
+  float y = lhs.y() - rhs.y();
+  float z = lhs.z() - rhs.z();
+  return Point3F(x, y, z);
+}
+
+// Subtract one point from another, producing a vector that represents the
+// distances between the two points along each axis.
+Vector3dF operator-(const Point3F& lhs, const Point3F& rhs) {
+  float x = lhs.x() - rhs.x();
+  float y = lhs.y() - rhs.y();
+  float z = lhs.z() - rhs.z();
+  return Vector3dF(x, y, z);
+}
+
+}  // namespace gfx