Add WebWidgetTestProxy.

content/renderer/render_widget.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_RENDERER_RENDER_WIDGET_H_
 #define CONTENT_RENDERER_RENDER_WIDGET_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 109 matching lines @@
                               blink::WebPopupType popup_type,
                               const blink::WebScreenInfo& screen_info);
 
   // Creates a new RenderWidget that will be attached to a RenderFrame.
   static RenderWidget* CreateForFrame(int routing_id,
                                       bool hidden,
                                       const blink::WebScreenInfo& screen_info,
                                       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);
+  using RenderWidgetCreatedCallback = void (*)(RenderWidget*);

[Łukasz Anforowicz, 2016/08/11 17:19:28]

nit: Would it be more accurate to call this RenderWidgetInitedCallback? (or
"Initialized" if "Inited" is not a word :-P).

[lfg, 2016/08/11 19:49:39]

Done.

+  static void InstallCreateHook(
+      CreateRenderWidgetFunction create_render_widget,
+      RenderWidgetCreatedCallback render_widget_created_callback);
+
   // Closes a RenderWidget that was created by |CreateForFrame|.
   // TODO(avi): De-virtualize this once RenderViewImpl has-a RenderWidget.
   // https://crbug.com/545684
   virtual void CloseForFrame();
 
   int32_t routing_id() const { return routing_id_; }
   void SetRoutingID(int32_t routing_id);
 
   CompositorDependencies* compositor_deps() const { return compositor_deps_; }
   blink::WebWidget* webwidget() const { return webwidget_; }
@@ skipping 652 matching lines @@
   // This reference is set by the RenderFrame and is used to query the IME-
   // related state from the plugin to later send to the browser.
   PepperPluginInstanceImpl* focused_pepper_plugin_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidget);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_WIDGET_H_