Bug 1618763 - Part 1. mHTMLInputInputmode should be lower case except to mozAwesomebar. r=masayuki

Since we cannot use HTMLInputElement.GetInputMode since we still support
mozAwesomebar, inputmode attribute isn't sanitized. Since I would like to reduce
comparing cost, it should be lower case except to mozAwesomebar.

Differential Revision: https://phabricator.services.mozilla.com/D67770

--HG--
extra : moz-landing-system : lando

dom/events/IMEStateManager.cpp

@@ -1287,10 +1287,14 @@ void IMEStateManager::SetIMEState(const IMEState& aState,
         nsContentUtils::IsChromeDoc(aContent->OwnerDoc())) {
       aContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::inputmode,
                                      context.mHTMLInputInputmode);
-      if (context.mHTMLInputInputmode.EqualsLiteral("mozAwesomebar") &&
-          !nsContentUtils::IsChromeDoc(aContent->OwnerDoc())) {
-        // mozAwesomebar should be allowed only in chrome
-        context.mHTMLInputInputmode.Truncate();
+      if (context.mHTMLInputInputmode.EqualsLiteral("mozAwesomebar")) {
+        if (!nsContentUtils::IsChromeDoc(aContent->OwnerDoc())) {
+          // mozAwesomebar should be allowed only in chrome
+          context.mHTMLInputInputmode.Truncate();
+        }
+      } else {
+        // Except to mozAwesomebar, inputmode should be lower case.
+        ToLowerCase(context.mHTMLInputInputmode);
       }
     }