[webkit-reviews] review requested: [Bug 22870] Animations and Transitions started in the same recalcStyle() cycle should have identical start times : [Attachment 26035] Patch, including LayoutTest files

[bugzilla-daemon at webkit.org]

Chris Marrin <cmarrin at apple.com> has asked Dave Hyatt <hyatt at apple.com> for
review:
Bug 22870: Animations and Transitions started in the same recalcStyle() cycle
should have identical start times
https://bugs.webkit.org/show_bug.cgi?id=22870

Attachment 26035: Patch, including LayoutTest files
https://bugs.webkit.org/attachment.cgi?id=26035&action=review

------- Additional Comments from Chris Marrin <cmarrin at apple.com>
	Fixed https://bugs.webkit.org/show_bug.cgi?id=22870
 
	I added a recalcStyleTime value to Document. This is updated
	at the start of the document's recalcStyle cycle and also
	when the document starts loading, since animations are started
	then as well. Then I always use that value when setting animation
	start times, so all animations started in the same cycle have the 
	same start time.

	The test cases checked in test this, but in the case of the 'left'
	test it actually doesn't make any difference in most cases. This is
	because values are clamped to whole pixels, so the start times would 
	have to be pretty far off for the test to fail using the old
	currentTime() model. Still, under really heavy load, it's possible for
	the test to fail without these changes.

	The 'transform' test is another story. It animates to the full
resolution
	of a floating point number, so the test fails miserably without this
	fix.