From 336b3a1f27b83df1c2f7a21aeac7d7fd9a194286 Mon Sep 17 00:00:00 2001
From: Markus Stange <mstange@themasta.com>
Date: Tue, 25 Oct 2016 13:44:19 -0400
Subject: [PATCH] Bug 1308859 - Do not hold on to pointers into mStyleStack
 across a presshell flush. r=jrmuizel

MozReview-Commit-ID: Cenm0J8rNq7

--HG--
extra : rebase_source : 8bf6cf74c270170ae211692337e791d8aef23ada
---
 dom/canvas/CanvasRenderingContext2D.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/dom/canvas/CanvasRenderingContext2D.h b/dom/canvas/CanvasRenderingContext2D.h
index 2db7285e3a5b..2ea4c5fd9d82 100644
--- a/dom/canvas/CanvasRenderingContext2D.h
+++ b/dom/canvas/CanvasRenderingContext2D.h
@@ -696,6 +696,7 @@ protected:
   /**
    * Update CurrentState().filter with the filter description for
    * CurrentState().filterChain.
+   * Flushes the PresShell, so the world can change if you call this function.
    */
   void UpdateFilter();
 
@@ -873,13 +874,12 @@ protected:
    * last call to UpdateFilter and now.
    */
   const gfx::FilterDescription& EnsureUpdatedFilter() {
-    const ContextState& state = CurrentState();
     bool isWriteOnly = mCanvasElement && mCanvasElement->IsWriteOnly();
-    if (state.filterSourceGraphicTainted != isWriteOnly) {
+    if (CurrentState().filterSourceGraphicTainted != isWriteOnly) {
       UpdateFilter();
     }
-    MOZ_ASSERT(state.filterSourceGraphicTainted == isWriteOnly);
-    return state.filter;
+    MOZ_ASSERT(CurrentState().filterSourceGraphicTainted == isWriteOnly);
+    return CurrentState().filter;
   }
 
   bool NeedToCalculateBounds()