Highlighting password field then making a Sticky Note via Safari Services exposes...

Highlighting password field then making a Sticky Note via Safari Services exposes password
https://bugs.webkit.org/show_bug.cgi?id=126946

Reviewed by Enrica Casucci.

Using the Services menu has a slightly different codepath than Editor::copy() does. This
patch duplicates the canCopy() check that Editor::copy() does.

Testing is not possible because the Services menu is not accessible to our tests.

* editing/mac/EditorMac.mm:
(WebCore::Editor::stringSelectionForPasteboard):
(WebCore::Editor::stringSelectionForPasteboardWithImageAltText):
(WebCore::Editor::dataSelectionForPasteboard):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@161925 268f45cc-cd09-0410-ab3c-d52691b4dbfc