Use TaskScheduler instead of blocking pool in shell_url_request_context_getter.cc.

content/shell/browser/shell_url_request_context_getter.cc

Index: content/shell/browser/shell_url_request_context_getter.cc
diff --git a/content/shell/browser/shell_url_request_context_getter.cc b/content/shell/browser/shell_url_request_context_getter.cc
index 3ace069acd312eb9a74f181c182a025896b1e620..4a5ac9a69486ed7bf8336d0d825804efbe39cc40 100644
--- a/content/shell/browser/shell_url_request_context_getter.cc
+++ b/content/shell/browser/shell_url_request_context_getter.cc
@@ -14,7 +14,7 @@
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_split.h"
 #include "base/strings/string_util.h"
-#include "base/threading/sequenced_worker_pool.h"
+#include "base/task_scheduler/post_task.h"
 #include "build/build_config.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/cookie_store_factory.h"
@@ -257,8 +257,12 @@ net::URLRequestContext* ShellURLRequestContextGetter::GetURLRequestContext() {
     set_protocol = job_factory->SetProtocolHandler(
         url::kFileScheme,
         base::MakeUnique<net::FileProtocolHandler>(
-            BrowserThread::GetBlockingPool()->GetTaskRunnerWithShutdownBehavior(
-                base::SequencedWorkerPool::SKIP_ON_SHUTDOWN)));
+            base::CreateTaskRunnerWithTraits(
+                base::TaskTraits()
+                    .MayBlock()
+                    .WithPriority(base::TaskPriority::BACKGROUND)

[Peter Beverloo, 2017/04/26 14:30:37]

The protocol handlers for file:// and content:// (Android-only) in //chrome are
also registered with BACKGROUND priority, but that seems odd for something that
will be considered for navigation? USER_VISIBLE seems more appropriate.

https://chromium.googlesource.com/chromium/src/+/bd0ab22004781d47c24045d1ac8d...

https://cs.chromium.org/chromium/src/chrome/browser/profiles/profile_io_data....

bauerb@ (who reviewed the other CL) agrees, so would you mind updating that here
any in //chrome/browser/profiles/profile_io_data.cc?

[fdoray, 2017/04/26 18:00:37]

Done. https://codereview.chromium.org/2845683002/

+                    .WithShutdownBehavior(
+                        base::TaskShutdownBehavior::SKIP_ON_SHUTDOWN))));
     DCHECK(set_protocol);
 #endif