Introduce FORCE_LTR_DIRECTIONALTY in Canvas.

For strings coming from webpage (such as alert in JS), its directionality is set according to the directionality of its first strong character's directionality.

For chrome's UI string, its directionality is set as RTL if the UI is RTL and the string contains  strong RTL characters.


BUG=91698
TEST=start chrome in RTL locale, check about:crash, "!" should be displayed at very left. check the directionality  of alert() with bidi text in LTR and RTL chrome, the directionality should be determined by its first strong directionality character.
Review URL: http://codereview.chromium.org/7655037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@97392 0039d316-1c4b-4281-b951-d872f2087c98
4 files changed