Revert of Add WebWidgetTestProxy.

content/renderer/render_widget.h

Index: content/renderer/render_widget.h
diff --git a/content/renderer/render_widget.h b/content/renderer/render_widget.h
index c9587d67175cee8c1e44c33d6449e4af32cbefa4..daee7170916a6f19d73599d623067aec40007639 100644
--- a/content/renderer/render_widget.h
+++ b/content/renderer/render_widget.h
@@ -127,18 +127,6 @@
                                       CompositorDependencies* compositor_deps,
                                       blink::WebLocalFrame* frame);
 
-  // Used by content_layouttest_support to hook into the creation of
-  // RenderWidgets.
-  using CreateRenderWidgetFunction =
-      RenderWidget* (*)(CompositorDependencies*,
-                        blink::WebPopupType,
-                        const blink::WebScreenInfo&,
-                        bool,
-                        bool,
-                        bool);
-  static void InstallCreateHook(
-      CreateRenderWidgetFunction create_render_widget);
-
   // Closes a RenderWidget that was created by |CreateForFrame|.
   // TODO(avi): De-virtualize this once RenderViewImpl has-a RenderWidget.
   // https://crbug.com/545684