Fix "unused variable" warnings.

chrome/renderer/plugins/chrome_plugin_placeholder.cc

 // Copyright 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 "chrome/renderer/plugins/chrome_plugin_placeholder.h"
 
 #include <memory>
 #include <utility>
 
 #include "base/command_line.h"
@@ skipping 45 matching lines @@
     blink::WebLocalFrame* frame,
     const blink::WebPluginParams& params,
     const std::string& html_data,
     const base::string16& title)
     : plugins::LoadablePluginPlaceholder(render_frame,
                                          frame,
                                          params,
                                          html_data),
       status_(ChromeViewHostMsg_GetPluginInfo_Status::kAllowed),
       title_(title),
-#if defined(ENABLE_PLUGIN_INSTALLATION)
-      placeholder_routing_id_(MSG_ROUTING_NONE),
-#endif
-      has_host_(false),
       context_menu_request_id_(0),
       ignore_updates_(false) {
   RenderThread::Get()->AddObserver(this);
 }
 
 ChromePluginPlaceholder::~ChromePluginPlaceholder() {
   RenderThread::Get()->RemoveObserver(this);
   if (context_menu_request_id_ && render_frame())
     render_frame()->CancelContextMenu(context_menu_request_id_);
 
@@ skipping 372 matching lines @@
 
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnablePluginPlaceholderTesting)) {
     builder.SetMethod<void (ChromePluginPlaceholder::*)()>(
         "didFinishIconRepositionForTesting",
         &ChromePluginPlaceholder::DidFinishIconRepositionForTestingCallback);
   }
 
   return builder;
 }