<https://webkit.org/b/120123> [BlackBerry] Incorrect origin of indexOfTile in LayerTiler can cause unnecessary texture jobs and waste memory

Patch by Jacky Jiang <zhajiang@blackberry.com> on 2013-08-21
Reviewed by Yong Li.
Internally reviewed by Arvid Nilsson.

JIRA 481356
The origin of indexOfTile(origin) is incorrect in these two places. For
example, if the maxXMaxYCorner of the rect is (768, 768), there can be
three other redundant indexOfTile (0, 1), (1, 0), (1, 1) which can cause
unnecessary texture jobs and waste memory.
The origin should be the top left of the bottom right pixel of a rect.

* platform/graphics/blackberry/LayerTiler.cpp:
(WebCore::LayerTiler::updateTextureContentsIfNeeded):
(WebCore::LayerTiler::processTextureJob):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@154418 268f45cc-cd09-0410-ab3c-d52691b4dbfc