From 6cc1a1d65cd2b9eaeeb82ac3fe62e8dfc6a9eb01 Mon Sep 17 00:00:00 2001
From: Andrii Kulian <akulian@google.com>
Date: Tue, 27 Dec 2016 23:52:59 -0800
Subject: [PATCH] Fix crash when removing a display with activities

When secondary display is removed current behavior is to
move its stacks to the primary display. This requires app
windows to be reparented, and there was a check missing
for app windows in DisplayContent.reParentWindowToken.

Test: bit FrameworksServicesTests:com.android.server.wm.DisplayContentTests
Test: #testMoveStackBetweenDisplays
Bug: 33677605
Change-Id: I2ac2cdba273134438c63385887a09c37d42017bb
---
 .../com/android/server/wm/DisplayContent.java | 18 +++-------
 .../server/wm/DisplayContentTests.java        | 35 +++++++++++++++++++
 2 files changed, 40 insertions(+), 13 deletions(-)

diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index 135a3dc9f02ae..ff841b147d9c4 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -712,19 +712,11 @@ class DisplayContent extends WindowContainer<DisplayContent.DisplayChildWindowCo
         if (prevDc == this) {
             return;
         }
-        if (prevDc != null && prevDc.mTokenMap.remove(token.token) != null) {
-            switch (token.windowType) {
-                case TYPE_WALLPAPER:
-                    prevDc.mBelowAppWindowsContainers.removeChild(token);
-                    break;
-                case TYPE_INPUT_METHOD:
-                case TYPE_INPUT_METHOD_DIALOG:
-                    prevDc.mImeWindowsContainers.removeChild(token);
-                    break;
-                default:
-                    prevDc.mAboveAppWindowsContainers.removeChild(token);
-                    break;
-            }
+        if (prevDc != null && prevDc.mTokenMap.remove(token.token) != null
+                && token.asAppWindowToken() == null) {
+            // Removed the token from the map, but made sure it's not an app token before removing
+            // from parent.
+            token.getParent().removeChild(token);
         }
 
         addWindowToken(token.token, token);
diff --git a/services/tests/servicestests/src/com/android/server/wm/DisplayContentTests.java b/services/tests/servicestests/src/com/android/server/wm/DisplayContentTests.java
index 01808cb7462d3..786c2bb06d96d 100644
--- a/services/tests/servicestests/src/com/android/server/wm/DisplayContentTests.java
+++ b/services/tests/servicestests/src/com/android/server/wm/DisplayContentTests.java
@@ -19,12 +19,16 @@ package com.android.server.wm;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
+import android.hardware.display.DisplayManagerGlobal;
 import android.platform.test.annotations.Presubmit;
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
+import android.view.Display;
+import android.view.DisplayInfo;
 
 import java.util.ArrayList;
 
+import static android.view.DisplayAdjustments.DEFAULT_DISPLAY_ADJUSTMENTS;
 import static android.view.WindowManager.LayoutParams.TYPE_BASE_APPLICATION;
 import static android.view.WindowManager.LayoutParams.TYPE_VOICE_INTERACTION;
 import static org.junit.Assert.assertEquals;
@@ -203,4 +207,35 @@ public class DisplayContentTests extends WindowTestsBase {
 
         voiceInteractionWindow.removeImmediately();
     }
+
+    @Test
+    public void testMoveStackBetweenDisplays() throws Exception {
+        // Create second display.
+        final Display display = new Display(DisplayManagerGlobal.getInstance(),
+                sDisplayContent.getDisplayId() + 1, new DisplayInfo(),
+                DEFAULT_DISPLAY_ADJUSTMENTS);
+        final DisplayContent dc = new DisplayContent(display, sWm, sLayersController,
+                new WallpaperController(sWm));
+        sWm.mRoot.addChild(dc, 1);
+
+        // Add stack with activity.
+        final TaskStack stack = createTaskStackOnDisplay(dc);
+        assertEquals(dc.getDisplayId(), stack.getDisplayContent().getDisplayId());
+        assertEquals(dc, stack.getParent().getParent());
+        assertEquals(dc, stack.getDisplayContent());
+
+        final Task task = createTaskInStack(stack, 0 /* userId */);
+        final TestAppWindowToken token = new TestAppWindowToken(dc);
+        task.addChild(token, 0);
+        assertEquals(dc, task.getDisplayContent());
+        assertEquals(dc, token.getDisplayContent());
+
+        // Move stack to first display.
+        sWm.moveStackToDisplay(stack.mStackId, sDisplayContent.getDisplayId());
+        assertEquals(sDisplayContent.getDisplayId(), stack.getDisplayContent().getDisplayId());
+        assertEquals(sDisplayContent, stack.getParent().getParent());
+        assertEquals(sDisplayContent, stack.getDisplayContent());
+        assertEquals(sDisplayContent, task.getDisplayContent());
+        assertEquals(sDisplayContent, token.getDisplayContent());
+    }
 }