Improve existing lock transition - remove black splash.

ash/wm/power_button_controller.h

Index: ash/wm/power_button_controller.h
diff --git a/ash/wm/power_button_controller.h b/ash/wm/power_button_controller.h
index eee5f1cd9ee832ca9cd4509402e9f008eeddec70..61124bcfb45772d4d064b3e07d34a82d61274db4 100644
--- a/ash/wm/power_button_controller.h
+++ b/ash/wm/power_button_controller.h
@@ -53,13 +53,27 @@ class ASH_EXPORT PowerButtonController : public aura::RootWindowObserver,
     ANIMATION_RESTORE,
   };
 
-  // Groups of containers that can be animated.
+  // Specific containers or group of containers that can be animated.

[Daniel Erat, 2012/09/04 16:40:18]

nit: s/group/groups/

[Nikita (slow), 2012/09/04 17:36:42]

Done.

   // Exposed here for TestApi::ContainerGroupIsAnimated().
   enum ContainerGroup {
-    ALL_CONTAINERS = 0,
-    SCREEN_LOCKER_CONTAINERS,
-    SCREEN_LOCKER_AND_RELATED_CONTAINERS,
-    ALL_BUT_SCREEN_LOCKER_AND_RELATED_CONTAINERS,
+    DESKTOP_WALLPAPER = 1 << 0,

[Daniel Erat, 2012/09/04 16:40:18]

use consistent terminology: you're using "background" for the window id but
"wallpaper" here

[Nikita (slow), 2012/09/04 17:36:42]

Done.

+
+    // All user session related containers including system background but
+    // not including desktop background (wallpaper).
+    NON_LOCK_SCREEN_CONTAINERS = 1 << 1,
+
+    // Desktop wallpaper is moved to this layer when screen is locked.

[Daniel Erat, 2012/09/04 16:40:18]

asked over IM, but perhaps you're not there: i didn't realize earlier that the
wallpaper was being moved between layers.  is there any reason that it can't
just be moved from NonLockScreenContainersContainer to
LockScreenBackgroundContainer, so that none of the changes to
PowerButtonController are necessary?  where's the change that does the moving?

[Nikita (slow), 2012/09/04 17:36:42]

http://codereview.chromium.org/10810039/
Discussed over IM.

+    // This layer is excluded from lock animation so that wallpaper stays as is,
+    // user session windows are hidden and lock UI is shown on top of it.
+    // This layer is included in shutdown animation.
+    LOCK_SCREEN_WALLPAPER = 1 << 2,

[Daniel Erat, 2012/09/04 16:40:18]

same background vs. wallpaper issue here

[Nikita (slow), 2012/09/04 17:36:42]

Done.

+
+    // Lock screen and lock screen modal containers.
+    LOCK_SCREEN_CONTAINERS = 1 << 3,
+
+    // Multiple system layers belong here like status, menu, tooltip
+    // and overlay layers.
+    LOCK_SCREEN_RELATED_CONTAINERS = 1 << 4,
   };
 
   // Helper class used by tests to access internal state.
@@ -112,10 +126,10 @@ class ASH_EXPORT PowerButtonController : public aura::RootWindowObserver,
       controller_->hide_background_layer_timer_.Stop();
     }
 
-    // Returns true if the given set of containers was last animated with
-    // |type| (probably; the analysis is fairly ad-hoc).
-    bool ContainerGroupIsAnimated(ContainerGroup group,
-                                  AnimationType type) const;
+    // Returns true if containers of a given |container_mask|
+    // was last animated with |type| (probably; the analysis is fairly ad-hoc).

[Daniel Erat, 2012/09/04 16:40:18]

nit: s/was/were/

[Nikita (slow), 2012/09/04 17:36:42]

Done.

+    // |container_mask| is a bitfield of a ContainerGroup.

[Daniel Erat, 2012/09/04 16:40:18]

nit: s/a ContainerGroup/ContainerGroups/

[Nikita (slow), 2012/09/04 17:36:42]

As discussed renamed to Container

+    bool ContainerGroupIsAnimated(int container_mask, AnimationType type) const;

[Daniel Erat, 2012/09/04 16:40:18]

nit: s/ContainerGroupIs/ContainerGroupsAre/

[Nikita (slow), 2012/09/04 17:36:42]

Done.

 
     // Returns true if |background_layer_| is non-NULL and visible.
     bool BackgroundLayerIsVisible() const;
@@ -130,6 +144,12 @@ class ASH_EXPORT PowerButtonController : public aura::RootWindowObserver,
     DISALLOW_COPY_AND_ASSIGN(TestApi);
   };
 
+  // Helper method that returns bitfield mask of all containers.

[Daniel Erat, 2012/09/04 16:40:18]

nit: s/returns/returns a/

[Nikita (slow), 2012/09/04 17:36:42]

Done.

+  static int GetAllContainersMask();
+
+  // Helper method that returns bitfield mask of all lock screen containers.

[Daniel Erat, 2012/09/04 16:40:18]

nit: s/returns/returns a/

the comment here makes it sound like this method just returns
LOCK_SCREEN_CONTAINERS.  change it to "mask including LOCK_SCREEN_WALLPAPER,
LOCK_SCREEN_CONTAINERS, and LOCK_SCREEN_RELATED_CONTAINERS", assuming that
that's what it does

[Nikita (slow), 2012/09/04 17:36:42]

Done.

+  static int GetAllScreenLockContainersMask();

[Daniel Erat, 2012/09/04 16:40:18]

nit: s/ScreenLock/LockScreen/, so this is consistent with the mask names

[Nikita (slow), 2012/09/04 17:36:42]

Done.

+
   PowerButtonController();
   virtual ~PowerButtonController();
 
@@ -213,10 +233,6 @@ class ASH_EXPORT PowerButtonController : public aura::RootWindowObserver,
   // Are we in the process of shutting the machine down?
   bool shutting_down_;
 
-  // Should we start |shutdown_timer_| when we receive notification that the
-  // screen has been locked?
-  bool should_start_shutdown_timer_after_lock_;

[Daniel Erat, 2012/09/04 16:40:18]

thanks for deleting this

-
   // Was a command-line switch set telling us that we're running on hardware
   // that misreports power button releases?
   bool has_legacy_power_button_;