Use TaskScheduler instead of blocking pool in native_message_process_host.cc.

chrome/browser/extensions/api/messaging/native_message_process_host.cc

Index: chrome/browser/extensions/api/messaging/native_message_process_host.cc
diff --git a/chrome/browser/extensions/api/messaging/native_message_process_host.cc b/chrome/browser/extensions/api/messaging/native_message_process_host.cc
index 1974d6abb78f694f5f2143e4af2324ba841eb322..04a75005dc8e5d5e36345d2a4b25c39eccc13658 100644
--- a/chrome/browser/extensions/api/messaging/native_message_process_host.cc
+++ b/chrome/browser/extensions/api/messaging/native_message_process_host.cc
@@ -13,7 +13,6 @@
 #include "base/logging.h"
 #include "base/process/kill.h"
 #include "base/task_scheduler/post_task.h"
-#include "base/threading/sequenced_worker_pool.h"
 #include "build/build_config.h"
 #include "chrome/browser/extensions/api/messaging/native_messaging_host_manifest.h"
 #include "chrome/browser/extensions/api/messaging/native_process_launcher.h"
@@ -146,10 +145,11 @@ void NativeMessageProcessHost::OnHostProcessLaunched(
   read_file_ = read_file.GetPlatformFile();
 #endif
 
-  scoped_refptr<base::TaskRunner> task_runner(
-      content::BrowserThread::GetBlockingPool()->
-          GetTaskRunnerWithShutdownBehavior(
-              base::SequencedWorkerPool::SKIP_ON_SHUTDOWN));
+  scoped_refptr<base::TaskRunner> task_runner(base::CreateTaskRunnerWithTraits(
+      base::TaskTraits()
+          .MayBlock()
+          .WithPriority(base::TaskPriority::BACKGROUND)

[Devlin, 2017/04/24 20:22:11]

This task can spawn a new process, which seems like it should be USER_VISIBLE.

[Sergey Ulanov, 2017/04/24 21:24:17]

Yes, this should be USER_VISIBLE. Depending on application that calls the API
user may notice when there is a delay.

[fdoray, 2017/04/27 13:06:39]

Done.

+          .WithShutdownBehavior(base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN)));
 
   read_stream_.reset(new net::FileStream(std::move(read_file), task_runner));
   write_stream_.reset(new net::FileStream(std::move(write_file), task_runner));