Add staggered workspace animation to keyguard unlock animation.

Added behind FeatureFlag.KEYGUARD_ANIMATION due to dependency on
Ie94ab8ecd35e9dcc28d0b8f7aaeb058e15b0f80b.

Added dynamic resource unlock_staggered_velocity_dp_per_s so that the
animation can be tuned.

Bug: 151238866
Change-Id: I4d349d32cc7d86be3cdc582c2a7c565be2931444
diff --git a/src/com/android/launcher3/config/FeatureFlags.java b/src/com/android/launcher3/config/FeatureFlags.java
index 8453c41..0237b50 100644
--- a/src/com/android/launcher3/config/FeatureFlags.java
+++ b/src/com/android/launcher3/config/FeatureFlags.java
@@ -83,6 +83,9 @@
     public static final BooleanFlag UNSTABLE_SPRINGS = getDebugFlag(
             "UNSTABLE_SPRINGS", false, "Enable unstable springs for quickstep animations");
 
+    public static final BooleanFlag KEYGUARD_ANIMATION = getDebugFlag(
+            "KEYGUARD_ANIMATION", false, "Enable animation for keyguard going away on wallpaper");
+
     public static final BooleanFlag ADAPTIVE_ICON_WINDOW_ANIM = getDebugFlag(
             "ADAPTIVE_ICON_WINDOW_ANIM", true, "Use adaptive icons for window animations.");