Revert "Web Animations: Timeline should not advance during task execution"
Revert "Web Animations: Fix error in clock update logic and re-enable timeline-time test"

This reverts r173583 and r173609. r173583 causes 
ImageResourceTest.MultipartImage to fail on Android debug, e.g.,
http://build.chromium.org/p/tryserver.chromium/builders/android_dbg_triggered_tests/builds/152167/steps/webkit_unit_tests/logs/stdio

TBR=dstockwell@chromium.org

Review URL: https://codereview.chromium.org/272543005

git-svn-id: svn://svn.chromium.org/blink/trunk@173685 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Regression(r169412): Fix serialization of frame / iframe

The frame / iframe src attribute value was not correctly updated upon
serializing because HTMLFrameElementBase::hasLegalLinkAttribute() was returning
true if the attribute name was 'href' instead of 'src'. The attribute was thus
not detected as a link attribute and its value was not correctly updated with
the path to the serialized frame.

R=tkent@chromium.org, adamk@chromium.org
BUG=370772
TEST=WebPageNewSerializeTest.SubFrameSerialization

Review URL: https://codereview.chromium.org/275433011

git-svn-id: svn://svn.chromium.org/blink/trunk@173686 bbb929c8-8fbe-4397-9dbb-9b2b20218538