From b4d95d7c9730b48dc4e19b10ee09e46d39343116 Mon Sep 17 00:00:00 2001
From: Michael Layzell <michael@thelayzells.com>
Date: Tue, 8 Sep 2015 14:22:02 -0400
Subject: [PATCH] Bug 1202794 - Explicitly clear array in
 SortChildrenBy3DZOrder to satisfy the move analysis, r=mattwoodrow

---
 gfx/layers/Layers.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/gfx/layers/Layers.cpp b/gfx/layers/Layers.cpp
index 296c7cdfdbe5..1ae18e7ee413 100644
--- a/gfx/layers/Layers.cpp
+++ b/gfx/layers/Layers.cpp
@@ -1197,6 +1197,12 @@ ContainerLayer::SortChildrenBy3DZOrder(nsTArray<Layer*>& aArray)
       if (toSort.Length() > 0) {
         SortLayersBy3DZOrder(toSort);
         aArray.AppendElements(Move(toSort));
+        // XXX The move analysis gets confused here, because toSort gets moved
+        // here, and then gets used again outside of the loop. To clarify that
+        // we realize that the array is going to be empty to the move checker,
+        // we clear it again here. (This method renews toSort for the move
+        // analysis)
+        toSort.ClearAndRetainStorage();
       }
       aArray.AppendElement(l);
     }