In some cases different fonts are selected to get width of string and
to draw text.
In Font.cpp calls, font get changed due to fallback font architecture.
When making calls we need to check if Unicode is present in primary font or not.
 In case of Ellipsis, we need to check if Ellipsis Unicode is present in primary font or not,
if not then use "Dot" Unicode, this is also suggested in CSS3 (http://www.w3.org/TR/2003/CR-css3-text-20030514/)

BUG=416425
TEST=fast/text/ellipsis-platform-font-change.html

Review URL: https://codereview.chromium.org/593673003

git-svn-id: svn://svn.chromium.org/blink/trunk@183597 bbb929c8-8fbe-4397-9dbb-9b2b20218538