Enabled expansion and dragging down when QS is expanded

Previously going to the full shade and expanding notifications
where disabled when QS was expanded even though there was enough
space to allow it. This is now allowed again in order to have
a consistent experience.

Bug: 19712809
Change-Id: Ie756d9c3fbf9dc2e60a05d02f0f4cc5dd6c7ebe0
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
index 711956a..4bc317a 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
@@ -1075,8 +1075,12 @@
     };
 
     private void animateHeaderSlidingIn() {
-        mHeaderAnimating = true;
-        getViewTreeObserver().addOnPreDrawListener(mStartHeaderSlidingIn);
+        // If the QS is already expanded we don't need to slide in the header as it's already
+        // visible.
+        if (!mQsExpanded) {
+            mHeaderAnimating = true;
+            getViewTreeObserver().addOnPreDrawListener(mStartHeaderSlidingIn);
+        }
     }
 
     private void animateHeaderSlidingOut() {