Ignore OnKeyEvent for VKEY_POWER because it is handled by PowerButtonEvent

ash/system/chromeos/power/tablet_power_button_controller.cc

Index: ash/system/chromeos/power/tablet_power_button_controller.cc
diff --git a/ash/system/chromeos/power/tablet_power_button_controller.cc b/ash/system/chromeos/power/tablet_power_button_controller.cc
index ece838bb265ef5fa3e0f89e0d112d9ff6016a2ee..de85547f46661cf63f62bae89d1183aebb18bd51 100644
--- a/ash/system/chromeos/power/tablet_power_button_controller.cc
+++ b/ash/system/chromeos/power/tablet_power_button_controller.cc
@@ -138,6 +138,9 @@ void TabletPowerButtonController::SuspendDone(
 }
 
 void TabletPowerButtonController::OnKeyEvent(ui::KeyEvent* event) {
+  if (event->key_code() == ui::VKEY_POWER)

[Daniel Erat, 2016/11/22 00:48:19]

please also document why these are ignored. something like this is fine:

  // Ignore key events generated by the power button since
  // power button activity is already handled by OnPowerButtonEvent().

[Qiang(Joe) Xu, 2016/11/22 01:02:50]

Done.

+    return;
+
   if (!IsTabletModeActive() && backlights_forced_off_)
     SetBacklightsForcedOff(false);
 }