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

ui/gfx/compositor/layer.cc

Index: ui/gfx/compositor/layer.cc
diff --git a/ui/gfx/compositor/layer.cc b/ui/gfx/compositor/layer.cc
index b49e642271e19f536d47895d50d13d7c2e26137d..3822fa44ef701c9fde434653a69a7c21529cd3a4 100644
--- a/ui/gfx/compositor/layer.cc
+++ b/ui/gfx/compositor/layer.cc
@@ -17,7 +17,7 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebSize.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebSolidColorLayer.h"
 #include "ui/base/animation/animation.h"
-#include "ui/gfx/canvas_skia.h"
+#include "ui/gfx/canvas.h"
 #include "ui/gfx/compositor/compositor_switches.h"
 #include "ui/gfx/compositor/layer_animator.h"
 #include "ui/gfx/interpolated_transform.h"
@@ -319,7 +319,7 @@ void Layer::SuppressPaint() {
 void Layer::paintContents(WebKit::WebCanvas* web_canvas,
                           const WebKit::WebRect& clip) {
   TRACE_EVENT0("ui", "Layer::paintContents");
-  gfx::CanvasSkia canvas(web_canvas);
+  gfx::Canvas canvas(web_canvas);
   if (delegate_)
     delegate_->OnPaintLayer(&canvas);
 }