Initialize TaskScheduler in Mash.

chrome/app/mash/mash_runner.cc

 // Copyright 2016 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 "chrome/app/mash/mash_runner.h"
 
 #include "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/debugger.h"
 #include "base/files/file_util.h"
 #include "base/i18n/icu_util.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/process/launch.h"
 #include "base/run_loop.h"
+#include "base/task_scheduler/task_scheduler.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "base/trace_event/trace_event.h"
 #include "components/tracing/common/trace_to_console.h"
 #include "components/tracing/common/tracing_switches.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/service_names.mojom.h"
 #include "mash/package/mash_packaged_service.h"
 #include "mojo/public/cpp/bindings/binding_set.h"
 #include "services/catalog/public/interfaces/catalog.mojom.h"
 #include "services/catalog/public/interfaces/constants.mojom.h"
 #include "services/service_manager/background/background_service_manager.h"
@@ skipping 92 matching lines @@
 MashRunner::~MashRunner() {}
 
 int MashRunner::Run() {
   if (IsChild())
     return RunChild();
   RunMain();
   return 0;
 }
 
 void MashRunner::RunMain() {
+  constexpr int kNumThreads = 3;

[sky, 2016/11/23 21:47:35]

Where does the 3 come from? Is there a constant else where we should be using?

[fdoray, 2016/11/23 21:53:43]

From the SequencedWorkerPool that TaskScheduler replaces
https://cs.chromium.org/chromium/src/services/service_manager/standalone/cont...


I didn't put TaskScheduler initialization in service_manager::Context because it
enables the post_task.h API for the whole process (would be weird to enable
post_task.h for the whole process when a Context is initialized for the whole
process - I prefer to put it here to make it clear that any code running in a
Mash process may use post_task.h).

+  base::TaskScheduler::CreateAndSetSimpleTaskScheduler(kNumThreads);
+  base::SequencedWorkerPool::EnableWithRedirectionToTaskSchedulerForProcess();
+
   // TODO(sky): refactor BackgroundServiceManager so can supply own context, we
   // shouldn't we using context as it has a lot of stuff we don't really want
   // in chrome.
   NativeRunnerDelegateImpl native_runner_delegate;
   service_manager::BackgroundServiceManager background_service_manager;
   std::unique_ptr<service_manager::BackgroundServiceManager::InitParams>
       init_params(new service_manager::BackgroundServiceManager::InitParams);
   init_params->native_runner_delegate = &native_runner_delegate;
   background_service_manager.Init(std::move(init_params));
   context_.reset(new service_manager::ServiceContext(
@@ skipping 22 matching lines @@
   CHECK(catalog_control->OverrideManifestPath(
       content::mojom::kRendererServiceName,
       GetPackageManifestPath(kChromeContentRendererPackageName)));
   CHECK(catalog_control->OverrideManifestPath(
       content::mojom::kUtilityServiceName,
       GetPackageManifestPath(kChromeContentUtilityPackageName)));
 
   // Ping mash_session to ensure an instance is brought up
   context_->connector()->Connect("mash_session");
   base::RunLoop().Run();
+
+  base::TaskScheduler::GetInstance()->Shutdown();
 }
 
 int MashRunner::RunChild() {
+  // TODO(fdoray): Add TaskScheduler initialization code in
+  // service_manager::ServiceRunner. TaskScheduler can't be initialized here
+  // because it wouldn't be visible to the service's dynamic library.
+  // https://crbug.com/664996
+
   base::FilePath path =
       base::CommandLine::ForCurrentProcess()->GetSwitchValuePath(
           switches::kChildProcess);
   if (base::PathExists(path))
     return service_manager::ChildProcessMain();
 
   // If the path doesn't exist - try launching this as a packaged service.
   base::i18n::InitializeICU();
   InitializeResources();
   service_manager::ChildProcessMainWithCallback(
@@ skipping 33 matching lines @@
     base::trace_event::TraceConfig trace_config =
         tracing::GetConfigForTraceToConsole();
     base::trace_event::TraceLog::GetInstance()->SetEnabled(
         trace_config,
         base::trace_event::TraceLog::RECORDING_MODE);
   }
 
   MashRunner mash_runner;
   return mash_runner.Run();
 }