ported from UXP:

- Issue #2790 - Part 5: Persistent highlight despite blur click (156c7550)
- Issue #2790 - Cleanup: Remove debugging lines (459ed6ea)
- Issue #2790 - Cleanup: Remove whitespaces (70cbf0df)
- Issue #2790 - Part 6: Highlight color change and remove important (61ad3b8d)
- Issue #2790 - Part 7: Setting of contrasting color and fixing of last commit's issues (61f92f89)

and added CallerType::System to GetValue()/GetValueInternal().

layout/style/nsCSSRuleUtils.cpp

@@ -571,7 +571,6 @@ nsCSSRuleUtils::StateSelectorMatches(Element* aElement,
   for (nsPseudoClassList* pseudoClass = aSelector->mPseudoClassList;
        pseudoClass;
        pseudoClass = pseudoClass->mNext) {
-    // --- Autofill explicit matching ---
     if (pseudoClass->mType == CSSPseudoClassType::autofill ||
         pseudoClass->mType == CSSPseudoClassType::mozAutofillHighlight) {
       // Match if the element has the autofill state, regardless of focus
@@ -580,7 +579,6 @@ nsCSSRuleUtils::StateSelectorMatches(Element* aElement,
       }
       continue; // This pseudo-class matches
     }
-    // --- End autofill explicit matching ---
     auto idx = static_cast<CSSPseudoClassTypeBase>(pseudoClass->mType);
     EventStates statesToCheck = nsCSSPseudoClasses::sPseudoClassStates[idx];
     if (!statesToCheck.IsEmpty() && !StateSelectorMatches(aElement,