[webkit-reviews] review requested: [Bug 10094] Japanese characters improperly rendering in TOT : [Attachment 9667] patch

[bugzilla-request-daemon at opendarwin.org]

Graham Dennis <Graham.Dennis at gmail.com> has asked  for review:
Bug 10094: Japanese characters improperly rendering in TOT
http://bugzilla.opendarwin.org/show_bug.cgi?id=10094

Attachment 9667: patch
http://bugzilla.opendarwin.org/attachment.cgi?id=9667&action=edit

------- Additional Comments from Graham Dennis <Graham.Dennis at gmail.com>
This bug only occurs when the first character of a text run is a decomposed
Japanese hiragana or katakana character with voice marks. The bug is caused
because WidthIterator::advance does not update the m_currentCharacter variable
while iterating, and then the call to WidthIterator::normalizeVoicingMarks
normalises the character starting at m_currentCharacter instead of starting at
currentCharacter. As a result, if the first character of a text run requires
normalising, all subsequent characters in the run will be displayed as being
identical to the first character (as m_currentCharacter will be 0).

This patch fixes the bug by turning the currentCharacter variable into an
argument to normalizeVoicingMarks.

A testcase has been included in the patch, however it must be run as a pixel
test for the test to actually check that the bug has been fixed.