Reviewed by Justin.

        Remove incorrect assertions.
        
        These assertions were made on the assumption that 
        TSM would always call with a range that was contained 
        by an editable region.
        
        TSM may call -[WebHTMLView characterIndexForPoint:] on a mouse
        event that is otherwise unrelated to editing, which may
        be outside the current editing region, triggering these 
        assertions.

        * page/mac/WebCoreFrameBridge.mm:
        (-[WebCoreFrameBridge convertToNSRange:]):

WebKit:

        Reviewed by Justin.
        
        Add checks to make sure we don't try to create, use
        or return invalid ranges to TSM when it calls us despite
        not currently being in an editable region.

        * WebView/WebHTMLView.mm:
        (isTextInput):
        (-[WebHTMLView textStorage]):
        (-[WebHTMLView firstRectForCharacterRange:]):
        (-[WebHTMLView selectedRange]):
        (-[WebHTMLView attributedSubstringFromRange:]):



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@22058 268f45cc-cd09-0410-ab3c-d52691b4dbfc