Allow CanvasSkia to bind to an existing SkCanvas.

ui/gfx/canvas.h

Index: ui/gfx/canvas.h
diff --git a/ui/gfx/canvas.h b/ui/gfx/canvas.h
index 5fa067e5bb9445a7275a3706c19557dd36cb201b..38ad3ac364b7557338af8fa9b5c008efcb3946d9 100644
--- a/ui/gfx/canvas.h
+++ b/ui/gfx/canvas.h
@@ -15,6 +15,8 @@
 #include "ui/base/ui_export.h"
 #include "ui/gfx/native_widget_types.h"
 
+class SkCanvas;
+
 namespace ui {
 class Transform;
 
@@ -233,6 +235,8 @@ class UI_EXPORT Canvas {
   // A quick and dirty way to obtain the underlying SkCanvas.
   virtual CanvasSkia* AsCanvasSkia();
   virtual const CanvasSkia* AsCanvasSkia() const;

[Ben Goodger (Google), 2011/10/05 17:11:45]

Did anyone use this for anything other than to get a SkCanvas? Can we just
remove this?

[piman, 2011/10/05 17:31:29]

I wanted to get rid of it, but there's a dozen or so calls that need this to
access a method of CanvasSkia that isn't an override of Canvas. Some of them
probably could be made that way, but others probably don't (like ExtractBitmap,
that returns a SkBitmap&), so I didn't push it. We could.

+  virtual SkCanvas* GetSkCanvas();
+  virtual const SkCanvas* GetSkCanvas() const;
 };
 
 class UI_EXPORT CanvasPaint {