[mathml] Add new math display values to PlatformEnumToCSSValueID

In r716655 new display attribute values math and inline-math
were introduced but they should also have been added to
PlatformEnumToCSSValueID to prevent running into a NOTREACHED.

Bug: 6606
Change-Id: Ic0a7c43389731aaf72ab075719cb83d3e75a45d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1939787Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Rob Buis <rbuis@igalia.com>
Cr-Commit-Position: refs/heads/master@{#719564}

third_party/blink/renderer/core/css/css_value_id_mappings.h

@@ -356,6 +356,10 @@ inline CSSValueID PlatformEnumToCSSValueID(EDisplay v) {
     return CSSValueID::kInlineGrid;
   if (v == EDisplay::kContents)
     return CSSValueID::kContents;
+  if (v == EDisplay::kMath)
+    return CSSValueID::kMath;
+  if (v == EDisplay::kInlineMath)
+    return CSSValueID::kInlineMath;
 
   NOTREACHED();
   return CSSValueID::kInline;