ui/gfx: Convert CreateCanvas to use gfx::Size.

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 e9a9ed578dfdfde1fab4b94b0af6d50f9d396cec..116b338ff6b8e739c080585b313aecc7e8cf2be3 100644
--- a/ui/gfx/compositor/layer.cc
+++ b/ui/gfx/compositor/layer.cc
@@ -412,8 +412,8 @@ void Layer::UpdateLayerCanvas() {
     invalid_rect_ = gfx::Rect();
     return;
   }
-  scoped_ptr<gfx::Canvas> canvas(gfx::Canvas::CreateCanvas(
-      draw_rect.width(), draw_rect.height(), false));
+  scoped_ptr<gfx::Canvas> canvas(gfx::Canvas::CreateCanvas(draw_rect.size(),
+                                                           false));
   canvas->Translate(gfx::Point().Subtract(draw_rect.origin()));
   delegate_->OnPaintLayer(canvas.get());
   SetCanvas(*canvas->GetSkCanvas(), draw_rect.origin());