Remove #ifs related to WebScrollOffsetAnimationCurve

This removes "#if WEB_SCROLL_OFFSET_ANIMATION_CURVE_IS_DEFINED"
lines added in http://crrev.com/112933005. These are no longer
needed since http://crrev.com/365903004 (which #defines
WEB_SCROLL_OFFSET_ANIMATION_CURVE_IS_DEFINED) has landed.

BUG=243871

Review URL: https://codereview.chromium.org/383503003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282354 0039d316-1c4b-4281-b951-d872f2087c98
6 files changed