LayoutNGView should increment Document::layout_blocks_counter_ng_

UMA Blink.Layout.NGRatio.Blocks has never been count LayoutNGView as an
NG block. This CL fixes it.

After we confirm Blink.Layout.NGRatio.Blocks becomes 100% for canary,
we'll remove Blink.Layout.NGRatio.Blocks.

(cherry picked from commit ed68d65)

Bug: 1067527, 1294155, 1375906
Change-Id: I5cecab76caa715f4fbc07b743e37f017b9fbc023
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3960191
Reviewed-by: Koji Ishii <kojii@chromium.org>
Auto-Submit: Kent Tamura <tkent@chromium.org>
Commit-Queue: Kent Tamura <tkent@chromium.org>
Commit-Queue: Koji Ishii <kojii@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1060258}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3963155
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Auto-Submit: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/branch-heads/5359@{#94}
Cr-Branched-From: 27d3765-refs/heads/main@{#1058933}

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

@@ -58,7 +58,7 @@ LayoutNGMixin<Base>::LayoutNGMixin(ContainerNode* node) : Base(node) {
   static_assert(
       std::is_base_of<LayoutBlock, Base>::value,
       "Base class of LayoutNGMixin must be LayoutBlock or derived class.");
-  if (node && node->IsElementNode())
+  if (node)
     Base::GetDocument().IncLayoutBlockCounterNG();
 }