[CSS Background] repeat: round should round the number of tiles to the nearest natura...

[CSS Background] repeat: round should round the number of tiles to the nearest natural number
https://bugs.webkit.org/show_bug.cgi?id=120668

Source/WebCore:

Patch by Andrei Parvu <parvu@adobe.com> on 2013-09-24
Reviewed by Darin Adler.

Tests already available in css3/masking and css3/background

* rendering/RenderBoxModelObject.cpp: Rounded the number of tiles to the nearest natural number.
(WebCore::RenderBoxModelObject::calculateBackgroundImageGeometry):

LayoutTests:

Changed the sizes of the images/masks in the tests to be compliant with the new behaviour.

Patch by Andrei Parvu <parvu@adobe.com> on 2013-09-24
Reviewed by Darin Adler.

* css3/background/background-repeat-round-auto1-expected.html:
* css3/background/background-repeat-round-auto2-expected.html:
* css3/background/background-repeat-round-border-expected.html:
* css3/background/background-repeat-round-content-expected.html:
* css3/background/background-repeat-round-padding-expected.html:
* css3/background/background-repeat-round-padding.html:
* css3/masking/mask-repeat-round-auto1-expected.html:
* css3/masking/mask-repeat-round-auto2-expected.html:
* css3/masking/mask-repeat-round-border-expected.html:
* css3/masking/mask-repeat-round-content-expected.html:
* css3/masking/mask-repeat-round-padding-expected.html:
* css3/masking/mask-repeat-round-padding.html:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@156322 268f45cc-cd09-0410-ab3c-d52691b4dbfc