Revert 113075 (requested by asvitkine) (requested by asvitkine) (requested by asvitkine) (request...

Revert 113075 (requested by asvitkine) (requested by asvitkine) (requested by asvitkine) (requested by asvitkine) (requested by asvitkine) (requested by asvitkine) (requested by asvitkine) (requested by asvitkine) (requested by asvitkine) - Improve RenderTextWin font fallback.

Don't use SCRIPT_UNDEFINED in the case of font fallback,
unless font fallback actually fails to return a script
that can display the characters. This fixes the problem
of some scripts not being properly displayed.

This actually makes RenderTextWin properly validate whether
a text position accepts a cursor, which caused several tests
to fail and revealed some additional issues in RenderTextWin.

The CL includes some modifications to address this.

Some tests are disabled under XP, see:
http://crbug.com/106450

Also, fixes some lint warnings.

BUG=90426
TEST=Run chrome.exe --use-pure-views and paste some Bengali
text into the omnibox. It should show up properly.

Review URL: http://codereview.chromium.org/8575020

TBR=asvitkine@chromium.org
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=113083