From 0e875d36c73dc4d68f758d38f41f9d2426c9da9c Mon Sep 17 00:00:00 2001
From: Kenny Guy <kennyguy@google.com>
Date: Mon, 26 Feb 2018 14:11:40 +0000
Subject: [PATCH] Ignore events when there is no focused stack.

Skip brightness slider events when there is no
focused activity stack.

Bug: 73825714
Test: atest SystemUIGoogleTests
Test: atest BrightnessTrackerTest
Change-Id: I87376bbab47545dbcd9be684d1c8174fc9c8d92f
---
 .../android/server/display/BrightnessTracker.java    | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/display/BrightnessTracker.java b/services/core/java/com/android/server/display/BrightnessTracker.java
index df60c6654c4ba..cabccf37ebaae 100644
--- a/services/core/java/com/android/server/display/BrightnessTracker.java
+++ b/services/core/java/com/android/server/display/BrightnessTracker.java
@@ -333,8 +333,16 @@ public class BrightnessTracker {
 
         try {
             final ActivityManager.StackInfo focusedStack = mInjector.getFocusedStack();
-            builder.setUserId(focusedStack.userId);
-            builder.setPackageName(focusedStack.topActivity.getPackageName());
+            if (focusedStack != null && focusedStack.topActivity != null) {
+                builder.setUserId(focusedStack.userId);
+                builder.setPackageName(focusedStack.topActivity.getPackageName());
+            } else {
+                // Ignore the event because we can't determine user / package.
+                if (DEBUG) {
+                    Slog.d(TAG, "Ignoring event due to null focusedStack.");
+                }
+                return;
+            }
         } catch (RemoteException e) {
             // Really shouldn't be possible.
             return;