ui/gfx: Make gfx::Canvas inherit from gfx::CanvasSkia.

ui/views/border.h

Index: ui/views/border.h
diff --git a/ui/views/border.h b/ui/views/border.h
index a362fcc0423cdd36fa1248baa4feb219d56515e9..ffb93b7a21b534ea8b447703d1d3d506a8ebc48d 100644
--- a/ui/views/border.h
+++ b/ui/views/border.h
@@ -11,7 +11,7 @@
 #include "ui/views/view.h"
 
 namespace gfx{
-class Canvas;
+class CanvasSkia;
 }
 
 namespace views {
@@ -59,7 +59,7 @@ class VIEWS_EXPORT Border {
   static Border* CreateBorderPainter(Painter* painter);
 
   // Renders the border for the specified view.
-  virtual void Paint(const View& view, gfx::Canvas* canvas) const = 0;
+  virtual void Paint(const View& view, gfx::CanvasSkia* canvas) const = 0;
 
   // Sets the specified insets to the the border insets.
   virtual void GetInsets(gfx::Insets* insets) const = 0;