allow_null_skbitmap_to_be_transferred_across_threads.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Yutaka Hirano <yhirano@chromium.org>
Date: Tue, 9 Nov 2021 09:03:17 +0000
Subject: Allow null SkBitmap to be transferred across threads

(cherry picked from commit dad0c0e5162bcc49b8f60354d3bca92224d8381b)

Bug: 1241091
Change-Id: Ie96932c14c8884d6d3eafa76dab5043e7aa31888
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3251815
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Yutaka Hirano <yhirano@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#936861}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3268018
Auto-Submit: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/branch-heads/4664@{#893}
Cr-Branched-From: 24dc4ee75e01a29d390d43c9c264372a169273a7-refs/heads/main@{#929512}

diff --git a/third_party/blink/renderer/platform/graphics/skia/skia_utils.h b/third_party/blink/renderer/platform/graphics/skia/skia_utils.h
index 3bd49cac3f5dfcad0fcc1140fcf876fe37558930..c037b85210bf2dedeb8478cf918633ad94885048 100644
--- a/third_party/blink/renderer/platform/graphics/skia/skia_utils.h
+++ b/third_party/blink/renderer/platform/graphics/skia/skia_utils.h
@@ -209,11 +209,13 @@ struct CrossThreadCopier<SkBitmap> {
 
   using Type = SkBitmap;
   static SkBitmap Copy(const SkBitmap& bitmap) {
-    CHECK(bitmap.isImmutable()) << "Only immutable bitmaps can be transferred.";
+    CHECK(bitmap.isImmutable() || bitmap.isNull())
+        << "Only immutable bitmaps can be transferred.";
     return bitmap;
   }
   static SkBitmap Copy(SkBitmap&& bitmap) {
-    CHECK(bitmap.isImmutable()) << "Only immutable bitmaps can be transferred.";
+    CHECK(bitmap.isImmutable() || bitmap.isNull())
+        << "Only immutable bitmaps can be transferred.";
     return std::move(bitmap);
   }
 };