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

chrome/browser/renderer_host/browser_render_process_host.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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "chrome/browser/renderer_host/browser_render_process_host.h"
 
 #include <algorithm>
@@ skipping 522 matching lines @@
     switches::kMessageLoopHistogrammer,
     switches::kEnableDCHECK,
     switches::kSilentDumpOnDCHECK,
     switches::kUseLowFragHeapCrt,
     switches::kEnableStatsTable,
     switches::kExperimentalSpellcheckerFeatures,
     switches::kDisableAudio,
     switches::kSimpleDataSource,
     switches::kEnableBenchmarking,
     switches::kInternalNaCl,
-    switches::kInternalPDF,
     switches::kInternalPepper,
     switches::kRegisterPepperPlugins,
     switches::kDisableByteRangeSupport,
     switches::kDisableDatabases,
     switches::kDisableDesktopNotifications,
     switches::kDisableWebSockets,
     switches::kDisableLocalStorage,
     switches::kDisableSessionStorage,
     switches::kDisableSharedWorkers,
     switches::kDisableApplicationCache,
@@ skipping 507 matching lines @@
         IPC::InvalidPlatformFileForTransit(),
         std::vector<std::string>(),
         std::string(),
         false));
   }
 }
 
 void BrowserRenderProcessHost::EnableAutoSpellCorrect(bool enable) {
   Send(new ViewMsg_SpellChecker_EnableAutoSpellCorrect(enable));
 }