Add IPC message to open chrome://plugins from a missing plug-in placeholder.

chrome/browser/plugin_observer.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/browser/plugin_observer.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_process.h"
@@ skipping 401 matching lines @@
 }
 
 bool PluginObserver::OnMessageReceived(const IPC::Message& message) {
   IPC_BEGIN_MESSAGE_MAP(PluginObserver, message)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_BlockedOutdatedPlugin,
                         OnBlockedOutdatedPlugin)
 #if defined(ENABLE_PLUGIN_INSTALLATION)
     IPC_MESSAGE_HANDLER(ChromeViewHostMsg_FindMissingPlugin,
                         OnFindMissingPlugin)
 #endif
+    IPC_MESSAGE_HANDLER(ChromeViewHostMsg_OpenAboutPlugins,
+                        OnOpenAboutPlugins)
+
     IPC_MESSAGE_UNHANDLED(return false)
   IPC_END_MESSAGE_MAP()
 
   return true;
 }
 
 void PluginObserver::OnBlockedOutdatedPlugin(const string16& name,
                                              const GURL& update_url) {
   InfoBarTabHelper* infobar_helper = tab_contents_->infobar_tab_helper();
   infobar_helper->AddInfoBar(update_url.is_empty() ?
@@ skipping 46 matching lines @@
         content::Referrer(web_contents()->GetURL(),
                           WebKit::WebReferrerPolicyDefault),
         NEW_FOREGROUND_TAB, content::PAGE_TRANSITION_TYPED, false));
   } else {
     browser::ShowTabModalConfirmDialog(
         new ConfirmInstallDialogDelegate(web_contents(), installer),
         tab_contents_);
   }
 }
 #endif  // defined(ENABLE_PLUGIN_INSTALLATION)
+
+void PluginObserver::OnOpenAboutPlugins() {
+    web_contents()->OpenURL(OpenURLParams(
+        GURL(chrome::kAboutPluginsURL),
+        content::Referrer(web_contents()->GetURL(),
+                          WebKit::WebReferrerPolicyDefault),
+        NEW_FOREGROUND_TAB, content::PAGE_TRANSITION_TYPED, false));
+}