Fixed the flickering of the corners when collapsing the shade

Previously the header was flickering as soon as the collaping
approached the top of the shade.

Fixes: 150177399
Test: visual
Change-Id: I84f3f66d2527b13e541c99c106492518a063a5d4

packages/SystemUI/src/com/android/systemui/statusbar/NotificationShelf.java

@@ -120,6 +120,10 @@ public class NotificationShelf extends ActivatableNotificationView implements
         setClipToPadding(false);
         mShelfIcons.setIsStaticLayout(false);
         setBottomRoundness(1.0f, false /* animate */);
+
+        // Setting this to first in section to get the clipping to the top roundness correct. This
+        // value determines the way we are clipping to the top roundness of the overall shade
+        setFirstInSection(true);
         initDimens();
     }