Bug 1900879 - part 2: Remove unused PaintTracker r=layout-reviewers,TYLin

Depends on D212742

Differential Revision: https://phabricator.services.mozilla.com/D212743

layout/painting/PaintTracker.cpp

@@ -1,13 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#include "mozilla/PaintTracker.h"
-
-namespace mozilla {
-
-int PaintTracker::gPaintTracker;
-
-}  // namespace mozilla

layout/painting/PaintTracker.h

@@ -1,31 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-#ifndef mozilla_PaintTracker_h
-#define mozilla_PaintTracker_h
-
-#include "mozilla/Attributes.h"
-#include "nsDebug.h"
-
-namespace mozilla {
-
-class MOZ_STACK_CLASS PaintTracker {
- public:
-  PaintTracker() { ++gPaintTracker; }
-  ~PaintTracker() {
-    NS_ASSERTION(gPaintTracker > 0, "Mismatched constructor/destructor");
-    --gPaintTracker;
-  }
-
-  static bool IsPainting() { return !!gPaintTracker; }
-
- private:
-  static int gPaintTracker;
-};
-
-}  // namespace mozilla
-
-#endif  // mozilla_PaintTracker_h

layout/painting/moz.build

@@ -29,10 +29,6 @@ EXPORTS += [
     "WindowRenderer.h",
 ]
 
-EXPORTS.mozilla += [
-    "PaintTracker.h",
-]
-
 UNIFIED_SOURCES += [
     "ActiveLayerTracker.cpp",
     "DashedCornerFinder.cpp",
@@ -47,7 +43,6 @@ UNIFIED_SOURCES += [
     "nsDisplayList.cpp",
     "nsDisplayListInvalidation.cpp",
     "nsImageRenderer.cpp",
-    "PaintTracker.cpp",
     "RetainedDisplayListBuilder.cpp",
     "WindowRenderer.cpp",
 ]