ABANDONED: chromeos: Resume displays when suspend is cancelled.

ash/system/chromeos/power/power_event_observer.cc

Index: ash/system/chromeos/power/power_event_observer.cc
diff --git a/ash/system/chromeos/power/power_event_observer.cc b/ash/system/chromeos/power/power_event_observer.cc
index 663a8a613876b67e12d9c7bb4aae4bf5a22c3336..768d8c28d5070cf8b275f1f6f948b2fd1210067d 100644
--- a/ash/system/chromeos/power/power_event_observer.cc
+++ b/ash/system/chromeos/power/power_event_observer.cc
@@ -9,6 +9,7 @@
 #include "ash/common/wm_shell.h"
 #include "ash/shell.h"
 #include "ash/wm/power_button_controller.h"
+#include "base/threading/thread_task_runner_handle.h"
 #include "chromeos/dbus/dbus_thread_manager.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_tree_host.h"
@@ -36,15 +37,14 @@ void ResumeRenderingRequests() {
     window->GetHost()->compositor()->SetVisible(true);
 }
 
-void OnSuspendDisplaysCompleted(const base::Closure& suspend_callback,
-                                bool status) {
-  suspend_callback.Run();
-}
-
 }  // namespace
 
 PowerEventObserver::PowerEventObserver()
-    : screen_locked_(false), waiting_for_lock_screen_animations_(false) {
+    : screen_locked_(false),
+      waiting_for_lock_screen_animations_(false),
+      suspend_displays_in_progress_(false),
+      should_undo_suspend_displays_(false),
+      weak_ptr_factory_(this) {
   chromeos::DBusThreadManager::Get()->GetPowerManagerClient()->AddObserver(
       this);
   chromeos::DBusThreadManager::Get()->GetSessionManagerClient()->AddObserver(
@@ -117,15 +117,34 @@ void PowerEventObserver::SuspendImminent() {
     StopRenderingRequests();
   }
 
+  // Ignore mouse events that might be generated by suspending the displays.
   ui::UserActivityDetector::Get()->OnDisplayPowerChanging();
-  Shell::GetInstance()->display_configurator()->SuspendDisplays(base::Bind(
-      &OnSuspendDisplaysCompleted, chromeos::DBusThreadManager::Get()
-                                       ->GetPowerManagerClient()
-                                       ->GetSuspendReadinessCallback()));
+
+  should_undo_suspend_displays_ = false;
+  undo_suspend_displays_callback_.Cancel();
+  if (!suspend_displays_in_progress_) {
+    suspend_displays_in_progress_ = true;
+    Shell::GetInstance()->display_configurator()->SuspendDisplays(base::Bind(
+        &PowerEventObserver::OnSuspendDisplaysCompleted,
+        weak_ptr_factory_.GetWeakPtr(), chromeos::DBusThreadManager::Get()
+                                            ->GetPowerManagerClient()
+                                            ->GetSuspendReadinessCallback()));
+  }
 }
 
-void PowerEventObserver::SuspendDone(const base::TimeDelta& sleep_duration) {
+void PowerEventObserver::ResumeDisplays() {
+  // If there's an async display-suspending task running, wait until it finishes
+  // to resume the displays.
+  if (suspend_displays_in_progress_) {
+    should_undo_suspend_displays_ = true;
+    return;
+  }
+
   Shell::GetInstance()->display_configurator()->ResumeDisplays();
+}
+
+void PowerEventObserver::SuspendDone(const base::TimeDelta& sleep_duration) {
+  ResumeDisplays();
   WmShell::Get()->system_tray_notifier()->NotifyRefreshClock();
 
   // If the suspend request was being blocked while waiting for the lock
@@ -154,4 +173,24 @@ void PowerEventObserver::ScreenIsUnlocked() {
   screen_locked_ = false;
 }
 
+void PowerEventObserver::OnSuspendDisplaysCompleted(
+    const base::Closure& suspend_callback,
+    bool status) {
+  suspend_displays_in_progress_ = false;
+
+  // If the suspend attempt completed while we were in the process of suspending
+  // displays, we need to resume them now. This needs to happen asynchronously,
+  // as ui::DisplayConfigurator doesn't support having new configure requests
+  // submitted while it's running callbacks from an earlier configure request.
+  if (should_undo_suspend_displays_) {
+    should_undo_suspend_displays_ = false;
+    undo_suspend_displays_callback_.Reset(base::Bind(
+        &PowerEventObserver::ResumeDisplays, weak_ptr_factory_.GetWeakPtr()));
+    base::ThreadTaskRunnerHandle::Get()->PostTask(
+        FROM_HERE, undo_suspend_displays_callback_.callback());
+  }
+
+  suspend_callback.Run();
+}
+
 }  // namespace ash