From a966f41d5c34dec55814ef224261b87343281c0d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Tue, 24 Sep 2019 16:50:02 +0000
Subject: [PATCH] Bug 1574004 - Ensure not to leak disposer if UI thread is
 shot down. r=snorp,agi

I've hit this in one of my try runs and looks trivial to fix.

The already_AddRefed destructor asserts when leaked.

We should just not allow to let it go out of scope without moving the pointer.

Differential Revision: https://phabricator.services.mozilla.com/D46942

--HG--
extra : moz-landing-system : lando
---
 widget/android/nsWindow.cpp | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/widget/android/nsWindow.cpp b/widget/android/nsWindow.cpp
index cd5ead250435..a6b8fcc3b6d2 100644
--- a/widget/android/nsWindow.cpp
+++ b/widget/android/nsWindow.cpp
@@ -428,6 +428,7 @@ class nsWindow::NPZCSupport final
   using Base::DisposeNative;
 
   void OnDetach(already_AddRefed<Runnable> aDisposer) {
+    RefPtr<Runnable> disposer = aDisposer;
     // There are several considerations when shutting down NPZC. 1) The
     // Gecko thread may destroy NPZC at any time when nsWindow closes. 2)
     // There may be pending events on the Gecko thread when NPZC is
@@ -468,7 +469,7 @@ class nsWindow::NPZCSupport final
 
       uiThread->Dispatch(NS_NewRunnableFunction(
           "NPZCSupport::OnDetach",
-          [npzc, disposer = RefPtr<Runnable>(aDisposer)] {
+          [npzc, disposer = std::move(disposer)] {
             npzc->SetAttached(false);
             disposer->Run();
           }));
@@ -852,6 +853,7 @@ class nsWindow::LayerViewSupport final
   using Base::DisposeNative;
 
   void OnDetach(already_AddRefed<Runnable> aDisposer) {
+    RefPtr<Runnable> disposer = aDisposer;
     if (RefPtr<nsThread> uiThread = GetAndroidUiThread()) {
       GeckoSession::Compositor::GlobalRef compositor(mCompositor);
       if (!compositor) {
@@ -860,7 +862,7 @@ class nsWindow::LayerViewSupport final
 
       uiThread->Dispatch(NS_NewRunnableFunction(
           "LayerViewSupport::OnDetach",
-          [compositor, disposer = RefPtr<Runnable>(aDisposer),
+          [compositor, disposer = std::move(disposer),
            results = &mCapturePixelsResults, window = &mWindow] {
             if (LockedWindowPtr lock{*window}) {
               while (!results->empty()) {