From 124a6df32374465189452f162ba58aca8373eb42 Mon Sep 17 00:00:00 2001
From: Sotaro Ikeda <sikeda@mozilla.com>
Date: Sun, 22 Feb 2015 08:53:37 -0800
Subject: [PATCH] Bug 1133426 - Care about new CompositorChild and
 CompositorParent re-creation.

---
 widget/nsBaseWidget.cpp | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/widget/nsBaseWidget.cpp b/widget/nsBaseWidget.cpp
index 89bbe74a3a21..5675f20a1a5b 100644
--- a/widget/nsBaseWidget.cpp
+++ b/widget/nsBaseWidget.cpp
@@ -181,21 +181,24 @@ nsBaseWidget::Shutdown()
   mShutdownObserver = nullptr;
 }
 
-static void DeferredDestroyCompositor(CompositorParent* aCompositorParent,
-                              CompositorChild* aCompositorChild)
+static void DeferredDestroyCompositor(nsRefPtr<CompositorParent> aCompositorParent,
+                                      nsRefPtr<CompositorChild> aCompositorChild)
 {
     // Bug 848949 needs to be fixed before
     // we can close the channel properly
     //aCompositorChild->Close();
-    aCompositorParent->Release();
-    aCompositorChild->Release();
 }
 
 void nsBaseWidget::DestroyCompositor()
 {
   if (mCompositorChild) {
-    mCompositorChild->SendWillStop();
-    mCompositorChild->Destroy();
+    nsRefPtr<CompositorChild> compositorChild = mCompositorChild.forget();
+    nsRefPtr<CompositorParent> compositorParent = mCompositorParent.forget();
+
+    compositorChild->SendWillStop();
+    // New LayerManager, CompositorParent and CompositorChild might be created
+    // as a result of internal GetLayerManager() call.
+    compositorChild->Destroy();
 
     // The call just made to SendWillStop can result in IPC from the
     // CompositorParent to the CompositorChild (e.g. caused by the destruction
@@ -204,13 +207,12 @@ void nsBaseWidget::DestroyCompositor()
     // events already in the MessageLoop get processed before the
     // CompositorChild is destroyed, so we add a task to the MessageLoop to
     // handle compositor desctruction.
+
+    // The DefferedDestroyCompositor task takes ownership of compositorParent and
+    // will release them when it runs.
     MessageLoop::current()->PostTask(FROM_HERE,
-               NewRunnableFunction(DeferredDestroyCompositor, mCompositorParent,
-                                   mCompositorChild));
-    // The DestroyCompositor task we just added to the MessageLoop will handle
-    // releasing mCompositorParent and mCompositorChild.
-    unused << mCompositorParent.forget();
-    unused << mCompositorChild.forget();
+               NewRunnableFunction(DeferredDestroyCompositor, compositorParent,
+                                   compositorChild));
   }
 }