Fix low risk nullable => non nullable change for NavigatorLanguage.language

third_party/WebKit/Source/core/frame/NavigatorLanguage.idl

Index: third_party/WebKit/Source/core/frame/NavigatorLanguage.idl
diff --git a/third_party/WebKit/Source/core/frame/NavigatorLanguage.idl b/third_party/WebKit/Source/core/frame/NavigatorLanguage.idl
index 97fda80ba39a8f934271fff391efdbdcf1b5f651..1eac0216a0469d26ee2be06777e23fee9a261ec9 100644
--- a/third_party/WebKit/Source/core/frame/NavigatorLanguage.idl
+++ b/third_party/WebKit/Source/core/frame/NavigatorLanguage.idl
@@ -8,7 +8,7 @@
     NoInterfaceObject,
     Exposed=(Window,Worker),
 ] interface NavigatorLanguage {
-    readonly attribute DOMString? language;
+    readonly attribute DOMString language;
     // TODO(foolip): |languages| should be FrozenArray<DOMString>.
     [CachedAttribute=hasLanguagesChanged] readonly attribute DOMString[] languages;
 };