Check if updating |CachedLayoutResult| failed for unexpected cause

r671460 (crrev.com/c/1670146) called |SetNeedsLayout| when
updating |CachedLayoutResult| failed for any reasons. It was
pointed out that we'd like to notice if it failed for other
reasons than |ComputeMinMax|, so this patch changes it to
|NOTREACHED()|.

Still calls |SetNeedsLayout()| because not doing so can lead
to bad results.

Change-Id: I39b77f748628efda354c64258dffbd92b8d59b1c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1673845Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#671678}

third_party/blink/renderer/core/layout/ng/ng_block_node.cc

@@ -1038,8 +1038,16 @@ scoped_refptr<const NGLayoutResult> NGBlockNode::RunLegacyLayout(
 
     // If |SetCachedLayoutResult| did not update cached |LayoutResult|,
     // |NeedsLayout()| flag should not be cleared.
-    if (needed_layout && layout_result != box_->GetCachedLayoutResult()) {
-      box_->SetNeedsLayout(layout_invalidation_reason::kUnknown);
+    if (needed_layout) {
+      if (constraint_space.IsIntermediateLayout()) {
+        DCHECK_NE(layout_result, box_->GetCachedLayoutResult());
+        box_->SetNeedsLayout(layout_invalidation_reason::kUnknown);
+      } else if (layout_result != box_->GetCachedLayoutResult()) {
+        // TODO(kojii): If we failed to update CachedLayoutResult for other
+        // reasons, we'd like to review it.
+        NOTREACHED();
+        box_->SetNeedsLayout(layout_invalidation_reason::kUnknown);
+      }
     }
   } else if (layout_result) {
     // OOF-positioned nodes have a two-tier cache, and their layout results