[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 5e7d8c86377a4d6a7c5546dcde02b6a76e6c71d4..c8b733d933a400369c020748765fc4480be64cd1 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -788,7 +788,7 @@ 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, 2015/04/21 02:25:58]

Not sure what you're trying to do here. GetMeaningFromKeyCode translates from a
Windows VKEY code + flags to a DOM |key| value, and optionally a corresponding
character code.

Under X11 the |key_code_| field is already derived from the X KeySym value, so
we've already lost information - we instead want to map the KeySym -> DOM |key|
directly.

[Habib Virji, 2015/04/29 16:05:18]

There was a following CL: 954943003 that was trying to get the mapping from
KeySym to DomKey https://codereview.chromium.org/954943003/patch/40001/20016

SInce Kevin CL has landed. I will update 954943003 accordingly. This will remain
same.

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