Comment why we need to update LengthConversionData for SetParentStyle

Remove the TODO for now.

Bug: 937104
Change-Id: If8683655efbde3ff716539461b1db38b38cea21a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3909678
Commit-Queue: Rune Lillesveen <futhark@chromium.org>
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1050202}

third_party/blink/renderer/core/css/resolver/style_resolver_state.cc

@@ -151,8 +151,7 @@ CSSToLengthConversionData StyleResolverState::UnzoomedLengthConversionData()
 void StyleResolverState::SetParentStyle(
     scoped_refptr<const ComputedStyle> parent_style) {
   parent_style_ = std::move(parent_style);
-  // TODO(crbug.com/937104): UpdateLengthConversionData() for both SetStyle()
-  // and SetParentStyle() is probably inefficient.
+  // Need to update conversion data for 'lh' units.
   UpdateLengthConversionData();
 }