Add new attention state to launcher

ui/base/animation/tween.h

Index: ui/base/animation/tween.h
diff --git a/ui/base/animation/tween.h b/ui/base/animation/tween.h
index b1641b55bf10a103a830f9df5419f7d5f2bfa4e9..e339c8137baf0cc96921f912bb7e1b461357c121 100644
--- a/ui/base/animation/tween.h
+++ b/ui/base/animation/tween.h
@@ -22,6 +22,7 @@ class UI_EXPORT Tween {
     EASE_IN_OUT,   // Slow in and out, fast in the middle.
     FAST_IN_OUT,   // Fast in and out, slow in the middle.
     EASE_OUT_SNAP, // Fast in, slow out, snap to final value.
+    SMOOTH_IN_OUT, // Smooth, consistent speeds in and out (sine wave).
     ZERO,          // Returns a value of 0 always.
   };