From b7a705dcefe0e7aa4437b8dd720bd3b1d324c22b Mon Sep 17 00:00:00 2001
From: sotaro <sotaro.ikeda.g@gmail.com>
Date: Wed, 18 Mar 2020 10:38:32 +0000
Subject: [PATCH] Bug 1623254 - Re-create DrawTarget of
 CanvasRenderingContext2D when the DrawTarget becomes invalid r=nical

Differential Revision: https://phabricator.services.mozilla.com/D67274

--HG--
extra : moz-landing-system : lando
---
 dom/canvas/CanvasRenderingContext2D.cpp | 2 +-
 gfx/2d/DrawTargetD2D1.cpp               | 5 ++++-
 gfx/2d/DrawTargetD2D1.h                 | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/dom/canvas/CanvasRenderingContext2D.cpp b/dom/canvas/CanvasRenderingContext2D.cpp
index 48f6bdb3b1a8..b1377577b4b4 100644
--- a/dom/canvas/CanvasRenderingContext2D.cpp
+++ b/dom/canvas/CanvasRenderingContext2D.cpp
@@ -1296,7 +1296,7 @@ bool CanvasRenderingContext2D::EnsureTarget(const gfx::Rect* aCoveredRect,
       RestoreClipsAndTransformToTarget();
     }
 
-    if (mTarget) {
+    if (mTarget && mTarget->IsValid()) {
       return true;
     }
   }
diff --git a/gfx/2d/DrawTargetD2D1.cpp b/gfx/2d/DrawTargetD2D1.cpp
index d86bd5b34b39..bdbcb4217c0c 100644
--- a/gfx/2d/DrawTargetD2D1.cpp
+++ b/gfx/2d/DrawTargetD2D1.cpp
@@ -90,6 +90,9 @@ DrawTargetD2D1::~DrawTargetD2D1() {
 }
 
 bool DrawTargetD2D1::IsValid() const {
+  if (mInitState != InitState::Uninitialized && !IsDeviceContextValid()) {
+    return false;
+  }
   if (NS_IsMainThread()) {
     // Uninitialized DTs are considered valid.
     return mInitState != InitState::Failure;
@@ -2274,7 +2277,7 @@ void DrawTargetD2D1::PushD2DLayer(ID2D1DeviceContext* aDC,
                  nullptr);
 }
 
-bool DrawTargetD2D1::IsDeviceContextValid() {
+bool DrawTargetD2D1::IsDeviceContextValid() const {
   uint32_t seqNo;
   return mDC && Factory::GetD2D1Device(&seqNo) && seqNo == mDeviceSeq;
 }
diff --git a/gfx/2d/DrawTargetD2D1.h b/gfx/2d/DrawTargetD2D1.h
index 972e5a6c265d..74b06fdeb800 100644
--- a/gfx/2d/DrawTargetD2D1.h
+++ b/gfx/2d/DrawTargetD2D1.h
@@ -244,7 +244,7 @@ class DrawTargetD2D1 : public DrawTarget {
 
   // This function is used to determine if the mDC is still valid; if it is
   // stale, we should avoid using it to execute any draw commands.
-  bool IsDeviceContextValid();
+  bool IsDeviceContextValid() const;
 
   IntSize mSize;