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

ui/gfx/blit.h

 // Copyright (c) 2011 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_BLIT_H_
 #define UI_GFX_BLIT_H_
 
 #include "ui/gfx/native_widget_types.h"
 #include "ui/base/ui_export.h"
 
 class SkCanvas;
 
 namespace gfx {
 
 class Point;
 class Rect;
+class Vector2d;
 
 // Blits a rectangle from the source context into the destination context.
 UI_EXPORT void BlitContextToContext(NativeDrawingContext dst_context,
                                     const Rect& dst_rect,
                                     NativeDrawingContext src_context,
                                     const Point& src_origin);
 
 // Blits a rectangle from the source context into the destination canvas.
 UI_EXPORT void BlitContextToCanvas(SkCanvas *dst_canvas,
                                    const Rect& dst_rect,
@@ skipping 10 matching lines @@
 UI_EXPORT void BlitCanvasToCanvas(SkCanvas *dst_canvas,
                                   const Rect& dst_rect,
                                   SkCanvas *src_canvas,
                                   const Point& src_origin);
 
 // Scrolls the given subset of the given canvas by the given amount.
 // The canvas should not have a clip or a transform applied, since platforms
 // may implement those operations differently.
 UI_EXPORT void ScrollCanvas(SkCanvas* canvas,
                             const Rect& clip,
-                            const Point& amount);
+                            const Vector2d& amount);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_BLIT_H_