Today we don't handle the omission of the 0% or 100% keyframe well. I believe the behavior should be that if you omit the 0% keyframe, the value for the properties being animated before the animation came into scope should be used. And if the 100% keyframe is omitted, I think the keyframe with the largest key time should be used.
Created attachment 23207 [details] Patch, including LayoutTest file
Comment on attachment 23207 [details] Patch, including LayoutTest file + if (rule->item(0)->key() != 0 || rule->item(rule->length()-1)->key() != 1) We usually write rule->item(0)->key() != 0 as just rule->item(0)->key(). You need spaces (rule->length()-1) here between length() and 1. r=me
Committed r36303 M WebCore/ChangeLog M WebCore/css/CSSStyleSelector.cpp M LayoutTests/ChangeLog A LayoutTests/animations/keyframes-to-missing.html A LayoutTests/animations/keyframes-from-missing.html A LayoutTests/animations/keyframes-to-missing-expected.txt A LayoutTests/animations/keyframes-from-missing-expected.txt