Block NPAPI plugins by default

content/shell/app/shell_main_delegate.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 "content/shell/app/shell_main_delegate.h"
 
 #include "base/base_switches.h"
 #include "base/command_line.h"
 #include "base/cpu.h"
 #include "base/files/file.h"
@@ skipping 167 matching lines @@
     command_line.AppendSwitch(cc::switches::kCompositeToMailbox);
 #endif
 
     command_line.AppendSwitch(switches::kEnableFileCookies);
 
     command_line.AppendSwitch(switches::kEnablePreciseMemoryInfo);
 
     command_line.AppendSwitchASCII(switches::kHostResolverRules,
                                    "MAP *.test 127.0.0.1");
 
+#if defined(OS_WIN) || defined(OS_MACOSX)
+    // TODO(wfh): crbug.com/295137 Remove this when NPAPI is gone.
+    command_line.AppendSwitch(switches::kEnableNpapi);
+#endif
+
     // Unless/until WebM files are added to the media layout tests, we need to
     // avoid removing MP4/H264/AAC so that layout tests can run on Android.
 #if !defined(OS_ANDROID)
     net::RemoveProprietaryMediaTypesAndCodecsForTests();
 #endif
 
     if (!BlinkTestPlatformInitialize()) {
       if (exit_code)
         *exit_code = 1;
       return true;
@@ skipping 122 matching lines @@
 ContentRendererClient* ShellMainDelegate::CreateContentRendererClient() {
   renderer_client_.reset(
       CommandLine::ForCurrentProcess()->HasSwitch(switches::kDumpRenderTree) ?
           new LayoutTestContentRendererClient :
           new ShellContentRendererClient);
 
   return renderer_client_.get();
 }
 
 }  // namespace content