Add lucid sleep flag and debugging helper

chrome/browser/chromeos/power/light_bar.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/chromeos/power/light_bar.h"
+
+#include <cstring>  // needed for strlen()
+
+#include "base/command_line.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/message_loop/message_loop.h"
+#include "chromeos/chromeos_switches.h"
+#include "chromeos/dbus/dbus_thread_manager.h"
+
+namespace chromeos {
+
+namespace {
+const int kDarkSuspendDelaySeconds = 4;
+const char kLightBarControlPath[] =
+    "/sys/devices/virtual/chromeos/cros_ec/lightbar/sequence";
+const char kKonamiCommand[] = "KONAMI";
+
+}  // namespace
+
+LightBar::LightBar()
+    : control_path_(base::FilePath(kLightBarControlPath)),
+      has_light_bar_(base::PathIsWritable(control_path_)) {
+  DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(this);
+}
+
+LightBar::~LightBar() {
+  DBusThreadManager::Get()->GetPowerManagerClient()->RemoveObserver(this);
+}
+
+void LightBar::DarkSuspendImminent() {
+  // The plan is to track the progress of push events and then re-suspend as
+  // soon as we know they have been processed.  In the meanwhile, we can hack
+  // around this by just having the light bar delay for a long time so that
+  // people can at least start playing around with this feature for their apps.
+  //
+  // TODO(chirantan): Remove this once we can accurately track the progress of
+  // push events.
+  base::MessageLoop::current()->PostDelayedTask(

[Daniel Erat, 2014/09/15 23:24:36]

move this to the end and only do it if the write was successful?

[Chirantan Ekbote, 2014/09/15 23:36:17]

The light bar and the delay are pretty much independent.  We always want to do
the delay because there is currently no way to actually track the progress of
events through chrome and this is a hacky workaround.  Flashing the light bar is
best effort on devices that have one and is mainly a debugging aid rather than
something necessary for the feature to work.

+      FROM_HERE,
+      DBusThreadManager::Get()
+          ->GetPowerManagerClient()
+          ->GetSuspendReadinessCallback(),
+      base::TimeDelta::FromSeconds(kDarkSuspendDelaySeconds));
+
+  if (!has_light_bar_)
+    return;
+
+  if (base::WriteFile(control_path_, kKonamiCommand, strlen(kKonamiCommand)) !=
+      static_cast<int>(strlen(kKonamiCommand)))
+    PLOG(WARNING) << "Unable to flash light bar during dark resume.";
+}
+
+}  // namespace chromeos