Make HolographicOutlineHelper a singleton.

It's a pretty heavy object, including three Paints at 74
bytes apiece, and we allocate one for every workspace and
every icon. We really only need one.

Change-Id: Ic9e12d478c3be27b13133718875c91540f7ccf4c
diff --git a/src/com/android/launcher3/BubbleTextView.java b/src/com/android/launcher3/BubbleTextView.java
index 7cac8a6..7c7d93e 100644
--- a/src/com/android/launcher3/BubbleTextView.java
+++ b/src/com/android/launcher3/BubbleTextView.java
@@ -45,7 +45,7 @@
 
     private int mPrevAlpha = -1;
 
-    private final HolographicOutlineHelper mOutlineHelper = new HolographicOutlineHelper();
+    private final HolographicOutlineHelper mOutlineHelper = HolographicOutlineHelper.obtain();
     private final Canvas mTempCanvas = new Canvas();
     private final Rect mTempRect = new Rect();
     private boolean mDidInvalidateForPressedState;