Remove Downcasting RVContextMenuBase in ContextMenuDeleagate implementations.

chrome/browser/ui/panels/panel_extension_browsertest.cc

 // 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.
 
 #include "base/command_line.h"
 #include "base/path_service.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/extensions/extension_browsertest.h"
@@ skipping 105 matching lines @@
 class PanelContextMenu : public RenderViewContextMenu {
  public:
   PanelContextMenu(content::RenderFrameHost* render_frame_host,
                    const content::ContextMenuParams& params)
       : RenderViewContextMenu(render_frame_host, params) {}
 
   bool HasCommandWithId(int command_id) {
     return menu_model_.GetIndexOfCommandId(command_id) != -1;
   }
 
+  void Show() override {}
+
  protected:
   // RenderViewContextMenu implementation.
   bool GetAcceleratorForCommandId(int command_id,
                                   ui::Accelerator* accelerator) override {
     return false;
   }
 };
 
 IN_PROC_BROWSER_TEST_F(PanelExtensionBrowserTest, BasicContextMenu) {
   ExtensionTestMessageListener listener("panel loaded", false);
@@ skipping 131 matching lines @@
   EXPECT_FALSE(menu->HasCommandWithId(IDC_CONTENT_CONTEXT_COPYLINKLOCATION));
 
   // Execute the extension's custom menu item and wait for the extension's
   // script to tell us its onclick fired.
   ExtensionTestMessageListener onclick_listener("clicked", false);
   int command_id = IDC_EXTENSIONS_CONTEXT_CUSTOM_FIRST;
   ASSERT_TRUE(menu->IsCommandIdEnabled(command_id));
   menu->ExecuteCommand(command_id, 0);
   EXPECT_TRUE(onclick_listener.WaitUntilSatisfied());
 }