Enable runtime features with status=test before WebKit

content/renderer/render_thread_impl.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/renderer/render_thread_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <map>
 #include <utility>
@@ skipping 1146 matching lines @@
 
   const base::CommandLine& command_line =
       *base::CommandLine::ForCurrentProcess();
 
 #ifdef ENABLE_VTUNE_JIT_INTERFACE
   if (command_line.HasSwitch(switches::kEnableVtune))
     gin::Debug::SetJitCodeEventHandler(vTune::GetVtuneCodeEventHandler());
 #endif
 
   SetRuntimeFeaturesDefaultsAndUpdateFromArgs(command_line);
+  GetContentClient()->renderer()->SetRuntimeFeatures();

[clamy, 2016/09/16 12:00:13]

Quick sanity check: we're sure the ContentRendererClient will have been properly
initialized at that time? (I'm not familiar with the order of initialization in
the renderer).

[jochen (gone - plz use gerrit), 2016/09/16 12:25:08]

yeah, that's guaranteed

 
   blink_platform_impl_.reset(new RendererBlinkPlatformImpl(
       renderer_scheduler_.get(),
       GetRemoteInterfaces()->GetWeakPtr()));
   blink::initialize(blink_platform_impl_.get());
 
   v8::Isolate* isolate = blink::mainThreadIsolate();
   isolate->SetCreateHistogramFunction(CreateHistogram);
   isolate->SetAddHistogramSampleFunction(AddHistogramSample);
   renderer_scheduler_->SetRAILModeObserver(this);
@@ skipping 1088 matching lines @@
   if (blink::mainThreadIsolate()) {
     blink::mainThreadIsolate()->MemoryPressureNotification(
         v8::MemoryPressureLevel::kCritical);
     blink::MemoryPressureNotificationToWorkerThreadIsolates(
         v8::MemoryPressureLevel::kCritical);
   }
 }
 
 
 }  // namespace content