Add -expected.txt for web-anim finishing-an-animation.html WPT test

This test has non-flaky failures, so we can track them directly and
don't need to disable the test in TestExpectations.

Bug: 772076
Change-Id: Idd071879e02acfff7e77a3b4e923d4fe98f34cbc
Reviewed-on: https://chromium-review.googlesource.com/926721Reviewed-by: Robert Flack <flackr@chromium.org>
Commit-Queue: Stephen McGruer <smcgruer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#537840}

third_party/WebKit/LayoutTests/TestExpectations

@@ -1485,7 +1485,6 @@ crbug.com/771977 external/wpt/web-animations/interfaces/Animation/onfinish.html
 crbug.com/772048 crbug.com/772060 external/wpt/web-animations/timing-model/animations/updating-the-finished-state.html [ Timeout ]
 crbug.com/772014 external/wpt/web-animations/animation-model/animation-types/interpolation-per-property.html [ Timeout ]
 crbug.com/772014 external/wpt/web-animations/animation-model/animation-types/addition-per-property.html [ Timeout ]
-crbug.com/772076 external/wpt/web-animations/timing-model/animations/finishing-an-animation.html [ Pass Failure ]
 crbug.com/771722 external/wpt/web-animations/timing-model/animations/the-current-time-of-an-animation.html [ Failure ]
 crbug.com/771722 crbug.com/771751 crbug.com/772060 external/wpt/web-animations/timing-model/animations/setting-the-start-time-of-an-animation.html [ Failure ]
 

third_party/WebKit/LayoutTests/external/wpt/web-animations/timing-model/animations/finishing-an-animation-expected.txt

+This is a testharness.js-based test.
+PASS Finishing an animation with a zero playback rate throws
+PASS Finishing an infinite animation throws
+PASS Finishing an animation seeks to the end time
+PASS Finishing an animation with a current time past the effect end jumps back to the end
+PASS Finishing a reversed animation jumps to zero time
+PASS Finishing a reversed animation with a current time less than zero makes it jump back to zero
+PASS Finishing a paused animation resolves the start time
+FAIL Finishing a pause-pending animation resolves the pending task immediately and update the start time assert_false: expected false got undefined
+FAIL Finishing a pause-pending animation with negative playback rate resolves the pending task immediately assert_false: expected false got undefined
+FAIL Finishing an animation while play-pending resolves the pending task immediately assert_false: expected false got undefined
+PASS Finishing an animation during an aborted pause makes it finished immediately
+PASS Finishing an animation resolves the finished promise synchronously
+PASS Finishing an animation without a target resolves the finished promise synchronously
+PASS A pending ready promise is resolved and not replaced when the animation is finished
+FAIL A pending playback rate should be applied immediately when an animation is finished promise_test: Unhandled rejection with value: object "TypeError: animation.updatePlaybackRate is not a function"
+FAIL An exception should be thrown if the effective playback rate is zero promise_test: Unhandled rejection with value: object "TypeError: animation.updatePlaybackRate is not a function"
+FAIL An exception should be thrown when finishing if the effective playback rate is positive and the target effect end is infinity promise_test: Unhandled rejection with value: object "TypeError: animation.updatePlaybackRate is not a function"
+FAIL An exception is NOT thrown when finishing if the effective playback rate is negative and the target effect end is infinity promise_test: Unhandled rejection with value: object "TypeError: animation.updatePlaybackRate is not a function"
+Harness: the test ran to completion.
+