Disallow posting tasks to SequencedWorkerPools by default.

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 12 matching lines @@
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/path_service.h"
 #include "base/process/process_metrics.h"
 #include "base/run_loop.h"
 #include "base/strings/string16.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/sys_string_conversions.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/threading/simple_thread.h"
 #include "base/threading/thread_local.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/trace_event/memory_dump_manager.h"
 #include "base/trace_event/trace_event.h"
 #include "base/values.h"
 #include "build/build_config.h"
 #include "cc/base/histograms.h"
 #include "cc/base/switches.h"
@@ skipping 858 matching lines @@
   ChildThreadImpl::current()->SetThreadPriority(
       categorized_worker_pool_->background_worker_thread_id(),
       base::ThreadPriority::BACKGROUND);
 #endif
 
   record_purge_suspend_metric_closure_.Reset(base::Bind(
       &RenderThreadImpl::RecordPurgeAndSuspendMetrics, base::Unretained(this)));
   is_renderer_suspended_ = false;
 
   base::MemoryCoordinatorClientRegistry::GetInstance()->Register(this);
+
+  // If this renderer doesn't run inside the browser process, enable
+  // SequencedWorkerPool. Otherwise, it should already have been enabled.
+  // TODO(fdoray): Remove this once the SequencedWorkerPool to TaskScheduler
+  // redirection experiment concludes https://crbug.com/622400.
+  if (!command_line.HasSwitch(switches::kSingleProcess))
+    base::SequencedWorkerPool::EnableForProcess();
 }
 
 RenderThreadImpl::~RenderThreadImpl() {
 }
 
 void RenderThreadImpl::Shutdown() {
   for (auto& observer : observers_)
     observer.OnRenderProcessShutdown();
 
   if (memory_observer_) {
@@ skipping 1561 matching lines @@
   }
 }
 
 void RenderThreadImpl::OnRendererInterfaceRequest(
     mojom::RendererAssociatedRequest request) {
   DCHECK(!renderer_binding_.is_bound());
   renderer_binding_.Bind(std::move(request));
 }
 
 }  // namespace content