Add lucid sleep flag and debugging helper

chrome/browser/chromeos/power/light_bar.cc

Index: chrome/browser/chromeos/power/light_bar.cc
diff --git a/chrome/browser/chromeos/power/light_bar.cc b/chrome/browser/chromeos/power/light_bar.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fce9171dcb2b1c05886a0a62b0dd9009d961da35
--- /dev/null
+++ b/chrome/browser/chromeos/power/light_bar.cc
@@ -0,0 +1,59 @@
+// 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"

[Lei Zhang, 2014/09/19 21:08:47]

Please be aware that this is going away. Use base/files/file_util.h in the
future. I had to removed all references, but they keep sneaking back in.

+#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(
+      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