Animate unlock icon while unlocking.

When the user reaches the threshold such that the gesture is accepted
as an unlock, the icon scales a bit and gets fully opaque. When the
user flings, it gets even larger and fades out.

Bug: 15163546
Change-Id: Icd963aa8f7268712f239b204cdfa61ebc2baf4d0
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelView.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelView.java
index ea8dd68..f43f348 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelView.java
@@ -56,7 +56,7 @@
     private float mExpandedHeight = 0;
     private boolean mJustPeeked;
     private boolean mClosing;
-    private boolean mTracking;
+    protected boolean mTracking;
     private boolean mTouchSlopExceeded;
     private int mTrackingPointer;
     protected int mTouchSlop;