Don't use command line flags for enabling the internal pdf plugin. Instead, ...

chrome/common/pref_names.cc

 // Copyright (c) 2010 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/common/pref_names.h"
 
 namespace prefs {
 
 // *************** PROFILE PREFS ***************
 // These are attached to the user profile
@@ skipping 310 matching lines @@
 const wchar_t kExtensionToolbarSize[] = L"extensions.toolbarsize";
 
 // Pref containing the directory for internal plugins as written to the plugins
 // list (below).
 const wchar_t kPluginsLastInternalDirectory[] =
     L"plugins.last_internal_directory";
 
 // List pref containing information (dictionaries) on plugins.
 const wchar_t kPluginsPluginsList[] = L"plugins.plugins_list";
 
+// When first shipped, the pdf plugin will be disabled by default.  When we
+// enable it by default, we'll want to do so only once.
+const wchar_t kPluginsEnabledInternalPDF[] = L"plugins.enabled_internal_pdf";
+
 // Boolean that indicates whether we should check if we are the default browser
 // on start-up.
 const wchar_t kCheckDefaultBrowser[] = L"browser.check_default_browser";
 
 #if defined(OS_MACOSX)
 // Boolean that indicates whether the application should show the info bar
 // asking the user to set up automatic updates when Keystone promotion is
 // required.
 const wchar_t kShowUpdatePromotionInfoBar[] =
     L"browser.show_update_promotion_info_bar";
@@ skipping 453 matching lines @@
 
 // The root URL of the cloud print service.
 const wchar_t kCloudPrintServiceURL[] = L"cloud_print.service_url";
 // The unique id for this instance of the cloud print proxy.
 const wchar_t kCloudPrintProxyId[] = L"cloud_print.proxy_id";
 // The human-readable name of the Cloud Print proxy. User-supplied.
 const wchar_t kCloudPrintProxyName[] = L"cloud_print.proxy_name";
 // The GAIA auth token (we may need to move it outside of prefs)
 const wchar_t kCloudPrintAuthToken[] = L"cloud_print_auth_token";
 }  // namespace prefs