Add multiple task queues for the IO thread

This will enable the same scheduling capabilities as we already have on
the UI thread.

Bug: 863341
Change-Id: Ice34f614d78321caabf0fac3c6b1d6a621abb712
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1598813
Reviewed-by: Jochen Eisinger <[email protected]>
Reviewed-by: Alex Clarke <[email protected]>
Reviewed-by: Gabriel Charette <[email protected]>
Commit-Queue: Carlos Caballero <[email protected]>
Cr-Commit-Position: refs/heads/master@{#663539}
diff --git a/content/browser/BUILD.gn b/content/browser/BUILD.gn
index 4aaa499..55f6b2a 100644
--- a/content/browser/BUILD.gn
+++ b/content/browser/BUILD.gn
@@ -1687,6 +1687,8 @@
     "sandbox_ipc_linux.h",
     "sandbox_parameters_mac.h",
     "sandbox_parameters_mac.mm",
+    "scheduler/browser_io_task_environment.cc",
+    "scheduler/browser_io_task_environment.h",
     "scheduler/browser_task_executor.cc",
     "scheduler/browser_task_executor.h",
     "scheduler/browser_task_queues.cc",