ABANDONED: chromeos: Resume displays when suspend is cancelled.

ash/system/chromeos/power/power_event_observer.h

Index: ash/system/chromeos/power/power_event_observer.h
diff --git a/ash/system/chromeos/power/power_event_observer.h b/ash/system/chromeos/power/power_event_observer.h
index eb5bc058a2556c237a959084b54ef96c4d910b9a..1ac40cfe20cd45f31bf37f1a8c0d3222b8454670 100644
--- a/ash/system/chromeos/power/power_event_observer.h
+++ b/ash/system/chromeos/power/power_event_observer.h
@@ -7,8 +7,10 @@
 
 #include "ash/ash_export.h"
 #include "base/callback.h"
+#include "base/cancelable_callback.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 #include "chromeos/dbus/power_manager_client.h"
 #include "chromeos/dbus/session_manager_client.h"
 
@@ -38,17 +40,42 @@ class ASH_EXPORT PowerEventObserver
   void ScreenIsLocked() override;
   void ScreenIsUnlocked() override;
 
+ private:
+  // Runs ui::DisplayConfigurator::ResumeDisplays() if possible (i.e.
+  // |suspend_displays_in_progress_| is false). Otherwise, sets
+  // |should_undo_suspend_displays_| so this method can be called again once the
+  // in-progress display-suspending finishes.
+  void ResumeDisplays();
+
+  // Callback for ui::DisplayConfigurator::SuspendDisplays().
+  void OnSuspendDisplaysCompleted(const base::Closure& suspend_callback,
+                                  bool status);
+
   // Is the screen currently locked?
   bool screen_locked_;
 
   // Have the lock screen animations completed?
   bool waiting_for_lock_screen_animations_;
 
+  // Is there an in-progress async call to
+  // ui::DisplayConfigurator::SuspendDisplays()?
+  bool suspend_displays_in_progress_;
+
+  // Do we need to undo an in-progress call to
+  // ui::DisplayConfigurator::SuspendDisplays() after it completes?
+  bool should_undo_suspend_displays_;
+
   // If set, called when the lock screen animations have completed to confirm
   // that the system is ready to be suspended.
   base::Closure screen_lock_callback_;
 
- private:
+  // Used by OnSuspendDisplaysCompleted() if |should_undo_suspend_displays_| is
+  // true to run ResumeDisplays(). The task is canceled if it's still pending
+  // when SuspendImminent() is called.
+  base::CancelableClosure undo_suspend_displays_callback_;
+
+  base::WeakPtrFactory<PowerEventObserver> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(PowerEventObserver);
 };