ui: Prefer +/- operators to apply offsets.

ui/gfx/point_base.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_POINT_BASE_H_
 #define UI_GFX_POINT_BASE_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 16 matching lines @@
 
   void set_x(Type x) { x_ = x; }
   void set_y(Type y) { y_ = y; }
 
   void Offset(Type delta_x, Type delta_y) {
     x_ += delta_x;
     y_ += delta_y;
   }
 
   void operator+=(const VectorClass& vector) {
-    Offset(vector.x(), vector.y());
+    x_ += vector.x();
+    y_ += vector.y();
   }
 
   void operator-=(const VectorClass& vector) {
-    Offset(-vector.x(), -vector.y());
+    x_ -= vector.x();
+    y_ -= vector.y();
   }
 
   bool IsOrigin() const {
     return x_ == 0 && y_ == 0;
   }
 
   VectorClass OffsetFromOrigin() const {
     return VectorClass(x_, y_);
   }
 
-  VectorClass OffsetFrom(const Class& other) const {
-    return VectorClass(x_ - other.x_, y_ - other.y_);
-  }
-
   // A point is less than another point if its y-value is closer
   // to the origin. If the y-values are the same, then point with
   // the x-value closer to the origin is considered less than the
   // other.
   // This comparison is required to use Point in sets, or sorted
   // vectors.
   bool operator<(const Class& rhs) const {
     return (y_ == rhs.y_) ? (x_ < rhs.x_) : (y_ < rhs.y_);
   }
 
  protected:
   PointBase(Type x, Type y) : x_(x), y_(y) {}
   // Destructor is intentionally made non virtual and protected.
   // Do not make this public.
   ~PointBase() {}
 
  private:
   Type x_;
   Type y_;
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_POINT_BASE_H_