Reviewed by Darin Adler.

        https://bugs.webkit.org/show_bug.cgi?id=32261
        Added ability to separate the autocomplete suggestion previewing from
        the actual accepting of the suggested value in HTMLInputElement.
        This element (it's single line text incarnation) can now
        be put in suggestion mode where renderer might display the suggested
        value without making it automatically exposed to JavaScript.

        No new tests. This new methods are not exposed yet. It's use will be
        platform specific. PopupMenu and Chromium specific changes will be
        separated based on Darin Adler's comments.

        * dom/InputElement.h:
        (WebCore::InputElementData::suggestedValue):
        (WebCore::InputElementData::setSuggestedValue):
        * html/HTMLInputElement.cpp:
        (WebCore::HTMLInputElement::suggestedValue):
        (WebCore::HTMLInputElement::setSuggestedValue):
        (WebCore::HTMLInputElement::setValue):
        (WebCore::HTMLInputElement::setValueFromRenderer):
        * html/HTMLInputElement.h:
        * rendering/RenderTextControlSingleLine.cpp:
        (WebCore::RenderTextControlSingleLine::updateFromElement):
        * wml/WMLInputElement.cpp:
        (WebCore::WMLInputElement::suggestedValue):
        * wml/WMLInputElement.h:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@52204 268f45cc-cd09-0410-ab3c-d52691b4dbfc