ozone: evdev: Add a couple more trace events

Add trace event inside each read notification for evdev.

BUG=none
TEST=chrome://tracing in link_freon

Review URL: https://codereview.chromium.org/1110693003

Cr-Commit-Position: refs/heads/master@{#327110}
bool EventReaderLibevdevCros::HasMouse() const {
  return has_mouse_;
}

bool EventReaderLibevdevCros::HasMouse() const {
  return has_mouse_;
}
