Allow for different rects when animating to a single task stack view and a multiple task stack view.

- Fixing regression in task bar enter animation duration
- Fixing issue with extra long titles in the task bar
- Cleaning up some constants and unused code
diff --git a/packages/SystemUI/src/com/android/systemui/recents/model/Task.java b/packages/SystemUI/src/com/android/systemui/recents/model/Task.java
index a0ff3b7..189f358 100644
--- a/packages/SystemUI/src/com/android/systemui/recents/model/Task.java
+++ b/packages/SystemUI/src/com/android/systemui/recents/model/Task.java
@@ -69,6 +69,10 @@
 
     TaskCallbacks mCb;
 
+    public Task() {
+        // Only used by RecentsService for task rect calculations.
+    }
+
     public Task(int id, boolean isActive, Intent intent, String activityTitle,
                 Bitmap activityIcon, int userId) {
         this.key = new TaskKey(id, intent);