Add support for KeyboardEvent.getModifierState()

Source/core/dom/KeyboardEvent.cpp

Index: Source/core/dom/KeyboardEvent.cpp
diff --git a/Source/core/dom/KeyboardEvent.cpp b/Source/core/dom/KeyboardEvent.cpp
index 5354fc0b67c6bfbeb189f44ac80b953c27678f90..1e766195a6960a61048222c0f4b666b970a77225 100644
--- a/Source/core/dom/KeyboardEvent.cpp
+++ b/Source/core/dom/KeyboardEvent.cpp
@@ -157,6 +157,8 @@ void KeyboardEvent::initKeyboardEvent(const AtomicString& type, bool canBubble,
 
 bool KeyboardEvent::getModifierState(const String& keyIdentifier) const
 {
+    // FIXME: The following keyIdentifiers are not supported yet (crbug.com/265458):
+    // "AltGraph", "CapsLock", "Fn", "NumLock", "ScrollLock", "SymbolLock", "OS".

[garykac, 2013/07/29 16:18:00]

Note that we're working to clarify some of these keys in the current DOM3 WD.

For example, the "Fn" key is a hardware key used on keyboards with a limited
amount of physical space. It is not exposed to the key events.

Please let me know if you're planning on doing any work on this soon.

     if (keyIdentifier == "Control")
         return ctrlKey();
     if (keyIdentifier == "Shift")