Trace MessageLoop::RunTask execution

Previously, we were only issuing trace events around the task execution
within TaskAnnotator::RunTask. However, this does not include time spent
in observers (see bug for details on how it bites).

BUG=508005

Review URL: https://codereview.chromium.org/1225333002

Cr-Commit-Position: refs/heads/master@{#338492}


CrOS-Libchrome-Original-Commit: 87a2c639ff073ed3194a788ee1eaf82aabe77bab
1 file changed
tree: e15ecf82f7d49693eb84bb1ea7dff39bac5b3af1
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/