ash: Pass more-detailed shutdown reasons to powerd.

Make ShutdownController pass the actual cause of a shutdown
request (power button, system tray, or login screen) to
powerd rather just a generic "UI request from ash" string.

Also get rid of an "unknown" ShutdownReason enum value that
looks like it was just used as an initial placeholder within
LockStateController.

Bug: none
Change-Id: I0760e68a6bf462c508d1f2d8740b8e6a1cf31191
Reviewed-on: https://chromium-review.googlesource.com/933546Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Qiang Xu <warx@google.com>
Commit-Queue: Dan Erat <derat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538896}

ash/BUILD.gn

@@ -457,6 +457,8 @@ component("ash") {
     "shell_port_mus.h",
     "shutdown_controller.cc",
     "shutdown_controller.h",
+    "shutdown_reason.cc",
+    "shutdown_reason.h",
     "sidebar/sidebar.cc",
     "sidebar/sidebar.h",
     "sidebar/sidebar_widget.cc",

ash/shutdown_controller.cc

@@ -11,6 +11,7 @@
 #include "ash/shutdown_reason.h"
 #include "ash/wm/lock_state_controller.h"
 #include "base/metrics/user_metrics.h"
+#include "base/strings/stringprintf.h"
 #include "base/sys_info.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "chromeos/dbus/power_manager_client.h"
@@ -42,19 +43,14 @@ void ShutdownController::ShutDownOrReboot(ShutdownReason reason) {
 
   // On real Chrome OS hardware the power manager handles shutdown.
   using chromeos::DBusThreadManager;
-  constexpr char kDescription[] = "UI request from ash";
+  std::string description = base::StringPrintf("UI request from ash: %s",
+                                               ShutdownReasonToString(reason));
   if (reboot_on_shutdown_) {
     DBusThreadManager::Get()->GetPowerManagerClient()->RequestRestart(
-        reason == ShutdownReason::UNKNOWN
-            ? power_manager::REQUEST_RESTART_OTHER
-            : power_manager::REQUEST_RESTART_FOR_USER,
-        kDescription);
+        power_manager::REQUEST_RESTART_FOR_USER, description);
   } else {
     DBusThreadManager::Get()->GetPowerManagerClient()->RequestShutdown(
-        reason == ShutdownReason::UNKNOWN
-            ? power_manager::REQUEST_SHUTDOWN_OTHER
-            : power_manager::REQUEST_SHUTDOWN_FOR_USER,
-        kDescription);
+        power_manager::REQUEST_SHUTDOWN_FOR_USER, description);
   }
 }
 

ash/shutdown_reason.cc

+// Copyright 2018 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 "ash/shutdown_reason.h"
+
+#include "base/logging.h"
+
+namespace ash {
+
+const char* ShutdownReasonToString(ShutdownReason reason) {
+  switch (reason) {
+    case ShutdownReason::POWER_BUTTON:
+      return "power button";
+    case ShutdownReason::LOGIN_SHUT_DOWN_BUTTON:
+      return "login shut down button";
+    case ShutdownReason::TRAY_SHUT_DOWN_BUTTON:
+      return "tray shut down button";
+  }
+  NOTREACHED() << "Invalid reason " << static_cast<int>(reason);
+  return "invalid";
+}
+
+}  // namespace ash

ash/shutdown_reason.h

@@ -8,12 +8,14 @@
 namespace ash {
 
 enum class ShutdownReason {
-  UNKNOWN,                 // Reason unknown or not applicable.
   POWER_BUTTON,            // User pressed the (physical) power button.
   LOGIN_SHUT_DOWN_BUTTON,  // User pressed the login screen shut down button.
   TRAY_SHUT_DOWN_BUTTON,   // User pressed the tray shut down button.
 };
 
+// Returns a string describing |reason|.
+const char* ShutdownReasonToString(ShutdownReason reason);
+
 }  // namespace ash
 
 #endif  // ASH_SHUTDOWN_REASON_H_

ash/wm/lock_state_controller.cc

@@ -273,6 +273,7 @@ void LockStateController::OnLockFailTimeout() {
 }
 
 void LockStateController::StartLockToShutdownTimer() {
+  DCHECK(shutdown_reason_);
   shutdown_after_lock_ = false;
   lock_to_shutdown_timer_.Stop();
   lock_to_shutdown_timer_.Start(
@@ -332,8 +333,9 @@ void LockStateController::StartRealShutdownTimer(bool with_animation_time) {
 void LockStateController::OnRealPowerTimeout() {
   VLOG(1) << "OnRealPowerTimeout";
   DCHECK(shutting_down_);
+  DCHECK(shutdown_reason_);
   // Shut down or reboot based on device policy.
-  shutdown_controller_->ShutDownOrReboot(shutdown_reason_);
+  shutdown_controller_->ShutDownOrReboot(*shutdown_reason_);
 }
 
 void LockStateController::StartCancellableShutdownAnimation() {

ash/wm/lock_state_controller.h

@@ -13,6 +13,7 @@
 #include "ash/wm/session_state_animator.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/optional.h"
 #include "base/time/time.h"
 #include "base/timer/elapsed_timer.h"
 #include "base/timer/timer.h"
@@ -197,7 +198,7 @@ class ASH_EXPORT LockStateController : public aura::WindowTreeHostObserver,
   bool shutting_down_ = false;
 
   // The reason (e.g. user action) for a pending shutdown.
-  ShutdownReason shutdown_reason_ = ShutdownReason::UNKNOWN;
+  base::Optional<ShutdownReason> shutdown_reason_;
 
   // Indicates whether controller should proceed to (cancellable) shutdown after
   // locking.