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}
void EventConverterEvdevImpl::ReleaseMouseButtons() {
  base::TimeDelta timestamp = ui::EventTimeForNow();
  for (int code = BTN_MOUSE; code < BTN_JOYSTICK; ++code)
    OnButtonChange(code, false /* down */, timestamp);
}

void EventConverterEvdevImpl::ReleaseMouseButtons() {
  base::TimeDelta timestamp = ui::EventTimeForNow();
  for (int code = BTN_MOUSE; code < BTN_JOYSTICK; ++code)
    OnButtonChange(code, false /* down */, timestamp);
}
