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

ui/views/view.h

Index: ui/views/view.h
diff --git a/ui/views/view.h b/ui/views/view.h
index c197033d086f42893dc68fecc99732447ba4df28..6b5f5aed44a15715b200beb654a69a216a992a71 100644
--- a/ui/views/view.h
+++ b/ui/views/view.h
@@ -33,7 +33,7 @@
 using ui::OSExchangeData;
 
 namespace gfx {
-class Canvas;
+class CanvasSkia;
 class Insets;
 class Path;
 }
@@ -457,7 +457,7 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   // for View coordinates and language direction as required, allows the View
   // to paint itself via the various OnPaint*() event handlers and then paints
   // the hierarchy beneath it.
-  virtual void Paint(gfx::Canvas* canvas);
+  virtual void Paint(gfx::CanvasSkia* canvas);
 
   // The background object is owned by this object and may be NULL.
   void set_background(Background* b) { background_.reset(b); }
@@ -945,24 +945,24 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
 
   // Responsible for calling Paint() on child Views. Override to control the
   // order child Views are painted.
-  virtual void PaintChildren(gfx::Canvas* canvas);
+  virtual void PaintChildren(gfx::CanvasSkia* canvas);
 
   // Override to provide rendering in any part of the View's bounds. Typically
   // this is the "contents" of the view. If you override this method you will
   // have to call the subsequent OnPaint*() methods manually.
-  virtual void OnPaint(gfx::Canvas* canvas);
+  virtual void OnPaint(gfx::CanvasSkia* canvas);
 
   // Override to paint a background before any content is drawn. Typically this
   // is done if you are satisfied with a default OnPaint handler but wish to
   // supply a different background.
-  virtual void OnPaintBackground(gfx::Canvas* canvas);
+  virtual void OnPaintBackground(gfx::CanvasSkia* canvas);
 
   // Override to paint a border not specified by SetBorder().
-  virtual void OnPaintBorder(gfx::Canvas* canvas);
+  virtual void OnPaintBorder(gfx::CanvasSkia* canvas);
 
   // Override to paint a focus border (usually a dotted rectangle) around
   // relevant contents.
-  virtual void OnPaintFocusBorder(gfx::Canvas* canvas);
+  virtual void OnPaintFocusBorder(gfx::CanvasSkia* canvas);
 
   // Accelerated painting ------------------------------------------------------
 
@@ -994,7 +994,7 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
   virtual void UpdateChildLayerBounds(const gfx::Point& offset);
 
   // Overridden from ui::LayerDelegate:
-  virtual void OnPaintLayer(gfx::Canvas* canvas) OVERRIDE;
+  virtual void OnPaintLayer(gfx::CanvasSkia* canvas) OVERRIDE;
 
   // Finds the layer that this view paints to (it may belong to an ancestor
   // view), then reorders the immediate children of that layer to match the
@@ -1131,7 +1131,7 @@ class VIEWS_EXPORT View : public ui::LayerDelegate,
 
   // Common Paint() code shared by accelerated and non-accelerated code paths to
   // invoke OnPaint() on the View.
-  void PaintCommon(gfx::Canvas* canvas);
+  void PaintCommon(gfx::CanvasSkia* canvas);
 
   // Tree operations -----------------------------------------------------------