Remove dead code in Display::CSSValueFromComputedStyleInternal

No need to check 'style.Display() == EDisplay::kBlockMath' inside a
conditional with the same condition.

Change-Id: I537e857a9b4b638f8bd13e8e51a4466b4c5e24be
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2452729Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Oriol Brufau <obrufau@igalia.com>
Cr-Commit-Position: refs/heads/master@{#814259}

third_party/blink/renderer/core/css/properties/longhands/longhands_custom.cc

@@ -2445,10 +2445,7 @@ const CSSValue* Display::CSSValueFromComputedStyleInternal(
 
   if (style.Display() == EDisplay::kBlockMath) {
     CSSValueList* values = CSSValueList::CreateSpaceSeparated();
-    if (style.Display() == EDisplay::kBlockMath)
-      values->Append(*CSSIdentifierValue::Create(CSSValueID::kBlock));
-    else
-      values->Append(*CSSIdentifierValue::Create(CSSValueID::kInline));
+    values->Append(*CSSIdentifierValue::Create(CSSValueID::kBlock));
     values->Append(*CSSIdentifierValue::Create(CSSValueID::kMath));
     return values;
   }