From a67e03a61cb29199ba06534c4792a3d0947be0f4 Mon Sep 17 00:00:00 2001
From: Jason Simmons <jason-simmons@users.noreply.github.com>
Date: Thu, 13 Aug 2020 11:06:02 -0700
Subject: [PATCH] Do not access members after calling ClearDartWrapper
 (flutter/engine#20465)

---
 engine/src/flutter/lib/ui/painting/canvas.cc  | 2 +-
 engine/src/flutter/lib/ui/painting/image.cc   | 2 +-
 engine/src/flutter/lib/ui/painting/picture.cc | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/engine/src/flutter/lib/ui/painting/canvas.cc b/engine/src/flutter/lib/ui/painting/canvas.cc
index 129226d36a4..01e6f5cf96a 100644
--- a/engine/src/flutter/lib/ui/painting/canvas.cc
+++ b/engine/src/flutter/lib/ui/painting/canvas.cc
@@ -486,10 +486,10 @@ void Canvas::drawShadow(const CanvasPath* path,
 }
 
 void Canvas::Invalidate() {
+  canvas_ = nullptr;
   if (dart_wrapper()) {
     ClearDartWrapper();
   }
-  canvas_ = nullptr;
 }
 
 }  // namespace flutter
diff --git a/engine/src/flutter/lib/ui/painting/image.cc b/engine/src/flutter/lib/ui/painting/image.cc
index 126205530fa..7da7c0ad029 100644
--- a/engine/src/flutter/lib/ui/painting/image.cc
+++ b/engine/src/flutter/lib/ui/painting/image.cc
@@ -37,8 +37,8 @@ Dart_Handle CanvasImage::toByteData(int format, Dart_Handle callback) {
 }
 
 void CanvasImage::dispose() {
-  ClearDartWrapper();
   image_.reset();
+  ClearDartWrapper();
 }
 
 size_t CanvasImage::GetAllocationSize() const {
diff --git a/engine/src/flutter/lib/ui/painting/picture.cc b/engine/src/flutter/lib/ui/painting/picture.cc
index 48dd11226cf..1285a6b0921 100644
--- a/engine/src/flutter/lib/ui/painting/picture.cc
+++ b/engine/src/flutter/lib/ui/painting/picture.cc
@@ -56,8 +56,8 @@ Dart_Handle Picture::toImage(uint32_t width,
 }
 
 void Picture::dispose() {
-  ClearDartWrapper();
   picture_.reset();
+  ClearDartWrapper();
 }
 
 size_t Picture::GetAllocationSize() const {