Use TaskScheduler instead of SequencedWorkerPool in task_manager_impl.cc.

chrome/browser/task_manager/sampling/task_manager_impl.cc

Index: chrome/browser/task_manager/sampling/task_manager_impl.cc
diff --git a/chrome/browser/task_manager/sampling/task_manager_impl.cc b/chrome/browser/task_manager/sampling/task_manager_impl.cc
index aab3f46770eaf7fd4be07856bc040329d76adf91..f5b3d11b95e43aaade9f223d5c6f35dde32b1a4a 100644
--- a/chrome/browser/task_manager/sampling/task_manager_impl.cc
+++ b/chrome/browser/task_manager/sampling/task_manager_impl.cc
@@ -11,7 +11,7 @@
 #include <vector>
 
 #include "base/containers/adapters.h"
-#include "base/threading/sequenced_worker_pool.h"
+#include "base/task_scheduler/post_task.h"
 #include "build/build_config.h"
 #include "chrome/browser/task_manager/providers/browser_process_task_provider.h"
 #include "chrome/browser/task_manager/providers/child_process_task_provider.h"
@@ -32,13 +32,6 @@ namespace task_manager {
 
 namespace {
 
-scoped_refptr<base::SequencedTaskRunner> GetBlockingPoolRunner() {
-  base::SequencedWorkerPool* blocking_pool =
-      content::BrowserThread::GetBlockingPool();
-  return blocking_pool->GetSequencedTaskRunner(
-      blocking_pool->GetSequenceToken());
-}
-
 base::LazyInstance<TaskManagerImpl>::DestructorAtExit
     lazy_task_manager_instance = LAZY_INSTANCE_INITIALIZER;
 
@@ -48,7 +41,8 @@ TaskManagerImpl::TaskManagerImpl()
     : on_background_data_ready_callback_(
           base::Bind(&TaskManagerImpl::OnTaskGroupBackgroundCalculationsDone,
                      base::Unretained(this))),
-      blocking_pool_runner_(GetBlockingPoolRunner()),
+      blocking_pool_runner_(base::CreateSequencedTaskRunnerWithTraits(
+          {base::MayBlock(), base::TaskPriority::BACKGROUND})),

[ncarter (slow), 2017/05/17 20:11:21]

I think SKIP_SHUTDOWN would be appropriate here.

While TaskManager updates are potentially user-visible while the UI is
displayed, we also have background data collection tasks that use this API, so I
think keeping this at BACKGROUND priority is the right call.

[fdoray, 2017/05/19 18:50:11]

Done.

Added this file to a list of files to refactor once TaskScheduler supports
mutually exclusive sequences running at different priorities.

       shared_sampler_(new SharedSampler(blocking_pool_runner_)),
       is_running_(false),
       weak_ptr_factory_(this) {