Fixed a flash of the preview image when going to the dialer

The preview image was animating even though it should not have
leading to a weird flash.

Bug: 17261091
Change-Id: I168eae25eb654ceb79e055fb0d0189c31cb0bb3d
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/KeyguardAffordanceView.java b/packages/SystemUI/src/com/android/systemui/statusbar/KeyguardAffordanceView.java
index 4a6bfa10..5878ae1 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/KeyguardAffordanceView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/KeyguardAffordanceView.java
@@ -163,6 +163,9 @@
 
     public void setPreviewView(View v) {
         mPreviewView = v;
+        if (mPreviewView != null) {
+            mPreviewView.setVisibility(INVISIBLE);
+        }
     }
 
     private void drawArrow(Canvas canvas) {
@@ -295,7 +298,7 @@
             duration = Math.min(duration, CIRCLE_DISAPPEAR_MAX_DURATION);
             animator.setDuration(duration);
             animator.start();
-            if (mPreviewView != null) {
+            if (mPreviewView != null && mPreviewView.getVisibility() == View.VISIBLE) {
                 mPreviewView.setVisibility(View.VISIBLE);
                 mPreviewClipper = ViewAnimationUtils.createCircularReveal(
                         mPreviewView, getLeft() + mCenterX, getTop() + mCenterY, mCircleRadius,