From 3e966e2996bddb573b9749ed2597d636bdba05c6 Mon Sep 17 00:00:00 2001
From: Vadim Caen <caen@google.com>
Date: Fri, 25 Feb 2022 15:14:24 +0100
Subject: [PATCH] Fix Activity leaking form OnBackInvokedCallbackWrapper

 - The callback was not removed on the server in the clear() method since mWindow and
   mWindowSession fields were cleared before
 - The wrapper class was not static, risking to leak it's outer class
   and its field.

Test: com.android.launcher3.ui.widget.RequestPinItemTest#testPinWidgetWithConfig
Fixes: 220385755
Change-Id: I3e5a81bf48c2272b1cb2b5a9f2ba940d0f794a6f
---
 .../window/WindowOnBackInvokedDispatcher.java | 74 +++++++++----------
 1 file changed, 35 insertions(+), 39 deletions(-)

diff --git a/core/java/android/window/WindowOnBackInvokedDispatcher.java b/core/java/android/window/WindowOnBackInvokedDispatcher.java
index 0503c406c2871..94e5ea960f4fe 100644
--- a/core/java/android/window/WindowOnBackInvokedDispatcher.java
+++ b/core/java/android/window/WindowOnBackInvokedDispatcher.java
@@ -76,9 +76,9 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
 
     /** Detaches the dispatcher instance from its window. */
     public void detachFromWindow() {
+        clear();
         mWindow = null;
         mWindowSession = null;
-        clear();
     }
 
     // TODO: Take an Executor for the callback to run on.
@@ -165,50 +165,13 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
             } else {
                 int priority = mAllCallbacks.get(callback);
                 mWindowSession.setOnBackInvokedCallback(
-                        mWindow, new OnBackInvokedCallbackWrapper(callback, priority), priority);
+                        mWindow, new OnBackInvokedCallbackWrapper(callback), priority);
             }
         } catch (RemoteException e) {
             Log.e(TAG, "Failed to set OnBackInvokedCallback to WM. Error: " + e);
         }
     }
 
-    private class OnBackInvokedCallbackWrapper extends IOnBackInvokedCallback.Stub {
-        private final OnBackInvokedCallback mCallback;
-        private final @Priority int mPriority;
-
-        OnBackInvokedCallbackWrapper(
-                @NonNull OnBackInvokedCallback callback, @Priority int priority) {
-            mCallback = callback;
-            mPriority = priority;
-        }
-
-        @NonNull
-        public OnBackInvokedCallback getCallback() {
-            return mCallback;
-        }
-
-        @Override
-        public void onBackStarted() throws RemoteException {
-            Handler.getMain().post(() -> mCallback.onBackStarted());
-        }
-
-        @Override
-        public void onBackProgressed(BackEvent backEvent)
-                throws RemoteException {
-            Handler.getMain().post(() -> mCallback.onBackProgressed(backEvent));
-        }
-
-        @Override
-        public void onBackCancelled() throws RemoteException {
-            Handler.getMain().post(() -> mCallback.onBackCancelled());
-        }
-
-        @Override
-        public void onBackInvoked() throws RemoteException {
-            Handler.getMain().post(() -> mCallback.onBackInvoked());
-        }
-    }
-
     @Override
     public OnBackInvokedCallback getTopCallback() {
         if (mAllCallbacks.isEmpty()) {
@@ -223,6 +186,39 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
         return null;
     }
 
+    private static class OnBackInvokedCallbackWrapper extends IOnBackInvokedCallback.Stub {
+        private final OnBackInvokedCallback mCallback;
+
+        OnBackInvokedCallbackWrapper(@NonNull OnBackInvokedCallback callback) {
+            mCallback = callback;
+        }
+
+        @NonNull
+        public OnBackInvokedCallback getCallback() {
+            return mCallback;
+        }
+
+        @Override
+        public void onBackStarted() {
+            Handler.getMain().post(() -> mCallback.onBackStarted());
+        }
+
+        @Override
+        public void onBackProgressed(BackEvent backEvent) {
+            Handler.getMain().post(() -> mCallback.onBackProgressed(backEvent));
+        }
+
+        @Override
+        public void onBackCancelled() {
+            Handler.getMain().post(() -> mCallback.onBackCancelled());
+        }
+
+        @Override
+        public void onBackInvoked() throws RemoteException {
+            Handler.getMain().post(() -> mCallback.onBackInvoked());
+        }
+    }
+
     /**
      * Returns if the legacy back behavior should be used.
      *