Add a task_scheduler tracing category which will record an extra event per task.

That event will contain ExecutionMode/SequenceToken and TaskPriority.

It would be better to tack an optional extra arg to the main task event but
tracing doesn't currently allow this (http://crbug.com/652692).

BUG=649084

Review-Url: https://codereview.chromium.org/2392903002
Cr-Commit-Position: refs/heads/master@{#423681}


CrOS-Libchrome-Original-Commit: b7555076c5684f2679c0f63be683cde91cf6e215
6 files changed
tree: 90d122fbe5f93361109081653f5a9203d1439259
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/