viz: CHECK that ScopedSkiaWriteAccess is defined

On Chrome OS, we're seeing a relatively rare crash on submitting an
SkiaOutputDeviceBufferQueue::Submit [1]. The stack trace from the
crashes is pretty inconclusive (no real line number). After looking
at the code, I suspect it's because ScopedSkiaWriteAccess is null,
but I'd like to upgrade the DCHECK to a CHECK here to confirm.

[1] https://bugs.chromium.org/p/chromium/issues/detail?id=1156158

Bug: 1156158
Change-Id: Ibacc53efed6a2fe899afb408692e87314ef98d0b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2643485Reviewed-by: Peng Huang <penghuang@chromium.org>
Commit-Queue: Brian Ho <hob@chromium.org>
Cr-Commit-Position: refs/heads/master@{#845866}

components/viz/service/display_embedder/output_presenter.cc

@@ -108,7 +108,16 @@ void OutputPresenter::Image::EndWriteSkia() {
 }
 
 void OutputPresenter::Image::PreGrContextSubmit() {
+  // TODO(crbug.com/1169364): On Chrome OS, this function crashes rarely
+  // (~1 CPM) and is hard to reproduce. The suspected root cause is a null
+  // |scoped_skia_write_access_|, but the crash stack traces are a bit too
+  // mangled to confirm. For better logging, promote the DCHECK to a CHECK
+  // until we figure out the root cause.
+#if BUILDFLAG(IS_CHROMEOS_ASH)
+  CHECK(scoped_skia_write_access_);
+#else
   DCHECK(scoped_skia_write_access_);
+#endif  // BUILDFLAG(IS_CHROMEOS_ASH)
   if (scoped_skia_write_access_->end_state()) {
     scoped_skia_write_access_->surface()->flush(
         {}, scoped_skia_write_access_->end_state());