[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 c26b9c97b7748719a0cff3dee816b32912524dff..4330e544a06ff7a512d3588ef00f048de27b430b 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -782,7 +782,7 @@ void KeyEvent::ApplyLayout() const {
   character_ = (IsControlDown() || !native_event()) ?
       GetCharacterFromKeyCode(key_code_, flags()) :
       GetCharacterFromXEvent(native_event());
-  // TODO(kpschoedel): set key_ field for X11.
+  GetMeaningFromKeyCode(key_code_, flags(), &key_, &character_);

[Wez, 2015/02/20 00:00:30]

GetMeaningFromKeyCode currently assumes a US English layout, hence the TODO that
Kevin put for the usage in the #else clause; suggest copying that TODO to this
call as well.

Since this code only works for US English layouts currently, we need to get it
working for general layouts before we make the |key| attribute available to JS,
really (or perhaps only make it available if we detect a US layout is in
effect?)

[Habib Virji, 2015/02/23 10:10:05]

I have started looking into enabling |key| attribute to other layout. Kevin has
forwarded me his current work and I am looking into it. 

Will prefer holding it enabled for all other layout before landing this. 

 #elif defined(USE_OZONE)
   KeyboardCode key_code;
   if (!KeyboardLayoutEngineManager::GetKeyboardLayoutEngine()->Lookup(