RenderWidget/RenderView: encapsulate ViewHostMsg_Show, etc, in a callback

content/public/test/render_view_test.cc

Index: content/public/test/render_view_test.cc
diff --git a/content/public/test/render_view_test.cc b/content/public/test/render_view_test.cc
index defddbdcb59b98365c958e654fff7263d4efb2b9..7a6915c278b2781e8ea3f5677c5d11aec3ed3a6e 100644
--- a/content/public/test/render_view_test.cc
+++ b/content/public/test/render_view_test.cc
@@ -314,8 +314,8 @@ void RenderViewTest::SetUp() {
   view_params.max_size = gfx::Size();
 
   // This needs to pass the mock render thread to the view.
-  RenderViewImpl* view =
-      RenderViewImpl::Create(compositor_deps_.get(), view_params, false);
+  RenderViewImpl* view = RenderViewImpl::Create(
+      compositor_deps_.get(), view_params, RenderWidget::ShowCallback());
   view_ = view;
 }