Prevent crash dialogs from appearing in demo mode

Bug: 62712426
Test: runtest -p com.android.server.am frameworks-services
Change-Id: I73162e6cabfc57ecf549c772fb4d00eb862814fb
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 803d8f0..84017e7 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -719,7 +719,9 @@
 
     public boolean canShowErrorDialogs() {
         return mShowDialogs && !mSleeping && !mShuttingDown
-                && !mKeyguardController.isKeyguardShowing();
+                && !mKeyguardController.isKeyguardShowing()
+                && !(UserManager.isDeviceInDemoMode(mContext)
+                        && mUserController.getCurrentUser().isDemo());
     }
 
     private static ThreadPriorityBooster sThreadPriorityBooster = new ThreadPriorityBooster(