Reviewed by Ken.

    Reviewed by Ken.

	- implemented enough of the NSTextInput protocol and added the
	proper calls to NSInputManager to allow input methods to
	work. However, the text is not marked yet.

        * WebView.subproj/WebHTMLViewInternal.h: Added new fields to track
	marked range.
        * WebView.subproj/WebHTMLView.m:
        (-[WebHTMLView markedRange]): Implemented
        (-[WebHTMLView conversationIdentifier]): Implemented
        (-[WebHTMLView hasMarkedText]): Implemented
        (-[WebHTMLView unmarkText]): Implemented
        (-[WebHTMLView setMarkedText:selectedRange:]): Implemented - does
	not yet handle attributes in attributed strings
        (-[WebHTMLView insertText:]): Modified to handle replacing or abandoning
	the marked text when set.
        (-[WebHTMLView _selectMarkedText]): new helper method, self-explanatory
        (-[WebHTMLView _setMarkedDOMRange:]): hitto.
        (-[WebHTMLView _selectRangeInMarkedText:]): ditto
        (-[WebHTMLView _discardMarkedText]): ditto
        (-[WebHTMLView _selectionIsInsideMarkedText]): ditto
        (-[WebHTMLView _updateSelectionForInputManager]): ditto

	- did a bit of refactoring while I was in here.

        * WebView.subproj/WebHTMLView.m:
        (-[WebHTMLView _shouldReplaceSelectionWithText:givenAction:]): added this new
	helper method to simplify the common case of calling the shouldInsertText: delegate
        (-[WebHTMLView pasteAsPlainText:]): use it
        (-[WebHTMLView insertTab:]): ditto
        (-[WebHTMLView insertNewline:]): ditto
        (-[WebHTMLView _changeWordCaseWithSelector:]): ditto
        (-[WebHTMLView _changeSpellingToWord:]): ditto
        (-[WebHTMLView _selectionChanged]): ditto

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@7184 268f45cc-cd09-0410-ab3c-d52691b4dbfc