[ETW Export] Add polling for ETW keyword.
commit3bd527974c0cea7b1e0e9965fa9e13823861ebb6
authorgeorgesak <georgesak@chromium.org>
Fri, 14 Aug 2015 15:52:37 +0000 (14 08:52 -0700)
committerCommit bot <commit-bot@chromium.org>
Fri, 14 Aug 2015 15:53:20 +0000 (14 15:53 +0000)
tree3e10e76d3200b25b4fb65821d9c6411b5962d97a
parent225925531da365c5ca1e083ed14188621dbb9139
[ETW Export] Add polling for ETW keyword.

This adds a background low-priority thread for each process that monitors the keyword and adjusts the categories accordingly. This allows users to start profiling (using UIForETW or Xpef directly) and specify which categories to enable, without having to restart Chrome.

Notes:
- TraceEventETWExport is a friend of TraceLog (see comment in code).
- ETW exporting still needs to be enabled using the command line or in about:flags.

BUG=491909

Review URL: https://codereview.chromium.org/1279353002

Cr-Commit-Position: refs/heads/master@{#343393}
base/trace_event/trace_event_etw_export_win.cc
base/trace_event/trace_event_etw_export_win.h
base/trace_event/trace_log.cc
base/trace_event/trace_log.h