Re-enable property tree verification for layout tests

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 175 matching lines @@
       command_line.AppendSwitch(switches::kDisableDisplayList2dCanvas);
     }
 
     command_line.AppendSwitch(switches::kEnableInbandTextTracks);
     command_line.AppendSwitch(switches::kMuteAudio);
 
     // TODO: crbug.com/311404 Make layout tests work w/ delegated renderer.
     command_line.AppendSwitch(switches::kDisableDelegatedRenderer);
     command_line.AppendSwitch(cc::switches::kCompositeToMailbox);
 
+    command_line.AppendSwitch(cc::switches::kEnablePropertyTreeVerification);
+
     command_line.AppendSwitch(switches::kEnablePreciseMemoryInfo);
 
     command_line.AppendSwitchASCII(switches::kHostResolverRules,
                                    "MAP *.test 127.0.0.1");
 
     // TODO(wfh): crbug.com/295137 Remove this when NPAPI is gone.
     command_line.AppendSwitch(switches::kEnableNpapi);
 
     // 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.
@@ skipping 130 matching lines @@
 ContentRendererClient* ShellMainDelegate::CreateContentRendererClient() {
   renderer_client_.reset(base::CommandLine::ForCurrentProcess()->HasSwitch(
                              switches::kRunLayoutTest)
                              ? new LayoutTestContentRendererClient
                              : new ShellContentRendererClient);
 
   return renderer_client_.get();
 }
 
 }  // namespace content