Give the main frame a RenderWidget.

ui/keyboard/content/keyboard_ui_content.cc

 // Copyright (c) 2013 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.
 
 #include "ui/keyboard/content/keyboard_ui_content.h"
 
 #include "base/command_line.h"
 #include "base/values.h"
 #include "content/public/browser/render_widget_host.h"
 #include "content/public/browser/render_widget_host_iterator.h"
@@ skipping 40 matching lines @@
   bool CanDragEnter(content::WebContents* source,
                     const content::DropData& data,
                     blink::WebDragOperationsMask operations_allowed) override {
     return false;
   }
 
   bool ShouldCreateWebContents(
       content::WebContents* web_contents,
       int route_id,
       int main_frame_route_id,
+      int main_frame_widget_route_id,
       WindowContainerType window_container_type,
       const std::string& frame_name,
       const GURL& target_url,
       const std::string& partition_id,
       content::SessionStorageNamespace* session_storage_namespace) override {
     return false;
   }
 
   bool IsPopupOrPanel(const content::WebContents* source) const override {
     return true;
@@ skipping 249 matching lines @@
           keyboard_controller()->keyboard_visible());
 }
 
 void KeyboardUIContent::AddBoundsChangedObserver(aura::Window* window) {
   aura::Window* target_window = window ? window->GetToplevelWindow() : nullptr;
   if (target_window)
     window_bounds_observer_->AddObservedWindow(target_window);
 }
 
 }  // namespace keyboard