Block NPAPI plug-ins in Metro mode instead of not loading them at all.

chrome/renderer/plugins/plugin_placeholder.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 "chrome/renderer/plugins/plugin_placeholder.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/json/string_escape.h"
 #include "base/string_piece.h"
@@ skipping 539 matching lines @@
 void PluginPlaceholder::LoadPlugin() {
   // This is not strictly necessary but is an important defense in case the
   // event propagation changes between "close" vs. "click-to-play".
   if (hidden_)
     return;
   if (!allow_loading_) {
     NOTREACHED();
     return;
   }
 
+  if (status_->value ==
+      ChromeViewHostMsg_GetPluginInfo_Status::kNpapiNotSupported) {
+#if defined(OS_WIN)
+    RenderThread::Get()->RecordUserMetrics("Metro_RestartOnDesktop_Plugin");
+    RenderThread::Get()->Send(

[cpu_(ooo_6.6-7.5), 2012/10/18 00:42:59]

we need a person from sec-team to approve this.

[Bernhard Bauer, 2012/10/18 09:13:57]

Chris, what's your opinion?

+        new ChromeViewHostMsg_RestartInDesktopMode(routing_id()));
+    return;
+#else
+    NOTREACHED();
+#endif
+  }
+
   // TODO(mmenke):  In the case of prerendering, feed into
   //                ChromeContentRendererClient::CreatePlugin instead, to
   //                reduce the chance of future regressions.
   WebPlugin* plugin =
       render_view()->CreatePlugin(frame_, plugin_info_, plugin_params_);
   ReplacePlugin(plugin);
 }
 
 void PluginPlaceholder::LoadCallback(const CppArgumentList& args,
                                      CppVariant* result) {
@@ skipping 60 matching lines @@
 bool PluginPlaceholder::IsYouTubeURL(const GURL& url,
                                        const std::string& mime_type) {
   std::string host = url.host();
   bool is_youtube = EndsWith(host, "youtube.com", true) ||
       EndsWith(host, "youtube-nocookie.com", true);
 
   return is_youtube && IsValidYouTubeVideo(url.path()) &&
       LowerCaseEqualsASCII(mime_type, kFlashPluginSwfMimeType);
 }
 #endif