Bug 1370802: There's actually no need for lang to be lowercased. r=heycam

MozReview-Commit-ID: KwtbLqR9Y81

--HG--
extra : rebase_source : 644eadfb0d20e5ee5e1b26eab348903e8033b868

dom/html/nsGenericHTMLElement.cpp

@@ -1224,19 +1224,8 @@ MapLangAttributeInto(const nsMappedAttributes* aAttributes, GenericSpecifiedValu
   }
   MOZ_ASSERT(langValue->Type() == nsAttrValue::eAtom);
   if (aData->ShouldComputeStyleStruct(NS_STYLE_INHERIT_BIT(Font))) {
-    nsIAtom* atom = langValue->GetAtomValue();
-
-    const nsDependentAtomString atomString(atom);
-    Maybe<nsCOMPtr<nsIAtom>> lowerAtom;
-    if (nsContentUtils::StringContainsASCIIUpper(atomString)) {
-      nsAutoString dest;
-      dest.SetCapacity(atomString.Length());
-      nsContentUtils::ASCIIToLower(atomString, dest);
-      lowerAtom.emplace(NS_AtomizeMainThread(dest));
-    }
-
-    aData->SetIdentAtomValueIfUnset(
-        eCSSProperty__x_lang, lowerAtom ? lowerAtom->get() : atom);
+    aData->SetIdentAtomValueIfUnset(eCSSProperty__x_lang,
+                                    langValue->GetAtomValue());
   }
   if (aData->ShouldComputeStyleStruct(NS_STYLE_INHERIT_BIT(Text))) {
     if (!aData->PropertyIsSet(eCSSProperty_text_emphasis_position)) {

layout/style/nsHTMLStyleSheet.cpp

@@ -593,17 +593,8 @@ nsHTMLStyleSheet::CalculateMappedServoDeclarations(nsPresContext* aPresContext)
 nsIStyleRule*
 nsHTMLStyleSheet::LangRuleFor(const nsIAtom* aLanguage)
 {
-  Maybe<nsCOMPtr<nsIAtom>> lowerAtom;
-  nsDependentAtomString langString(aLanguage);
-  if (nsContentUtils::StringContainsASCIIUpper(langString)) {
-    nsString dest;
-    nsContentUtils::ASCIIToLower(langString, dest);
-    lowerAtom.emplace(NS_AtomizeMainThread(dest));
-  }
-
-  const nsIAtom* key = lowerAtom ? *lowerAtom : aLanguage;
   auto entry =
-    static_cast<LangRuleTableEntry*>(mLangRuleTable.Add(key, fallible));
+    static_cast<LangRuleTableEntry*>(mLangRuleTable.Add(aLanguage, fallible));
   if (!entry) {
     NS_ASSERTION(false, "out of memory");
     return nullptr;

layout/style/nsRuleNode.cpp

@@ -3607,9 +3607,6 @@ nsRuleNode::SetFont(nsPresContext* aPresContext, GeckoStyleContext* aContext,
   // This is not a real CSS property, it is an HTML attribute mapped to CSS.
   const nsCSSValue* langValue = aRuleData->ValueForLang();
   if (eCSSUnit_AtomIdent == langValue->GetUnit()) {
-    MOZ_ASSERT(!nsContentUtils::StringContainsASCIIUpper(
-                  nsDependentAtomString(langValue->GetAtomValue())));
-
     aFont->mLanguage = langValue->GetAtomValue();
     aFont->mExplicitLanguage = true;
   }