[KeyboardEvent] Add embedder APIs to translate between Dom |key| enum and strings

ui/events/event.cc

Index: ui/events/event.cc
diff --git a/ui/events/event.cc b/ui/events/event.cc
index 953220d0a634f1de2ae7ec3ca738dfc34a879839..7da33774861e27617b3d637175ad54b8a0f82751 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -838,6 +838,16 @@ base::char16 KeyEvent::GetCharacter() const {
   return character_;
 }
 
+int KeyEvent::GetDomKeyOrCharacter() const {
+  // Determination of character_ and key_ may be done lazily.
+  base::char16 dom_char = GetCharacter();
+  ui::DomKey dom_key = GetDomKey();
+  if (dom_key == DomKey::CHARACTER)
+    return dom_char + static_cast<int>(DomKey::CHARACTER);
+  else
+    return static_cast<int>(dom_key);
+}
+
 base::char16 KeyEvent::GetText() const {
   if ((flags() & EF_CONTROL_DOWN) != 0) {
     base::char16 character;