Also failing on WebKit Linux Trusty Leak. Here's the diff:

--- /b/s/w/ioqsjMmC/layout-test-results/inspector-protocol/animation/animation-multiple-frames-expected.txt
+++ /b/s/w/ioqsjMmC/layout-test-results/inspector-protocol/animation/animation-multiple-frames-actual.txt
@@ -16,7 +16,7 @@
 Frame appended
 Animation started: start time is valid
 Frame appended
-Animation started: start time is valid
+Animation started: invalid startTime!268.208000000052.268.208000000208
 Frame appended
 Animation started: start time is valid
 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/16a17d6847498a28b3d5ddb182d5b66adb76e954

commit 16a17d6847498a28b3d5ddb182d5b66adb76e954
Author: Greg Thompson <grt@chromium.org>
Date: Wed Jun 27 10:05:16 2018

inspector-protocol/animation/animation-multiple-frames.js is flaky.

BUG= 856955 
TBR=grt@chromium.org

Change-Id: I3dc85cc564100b27fc4c3cd2a584952c48dfb981
Reviewed-on: https://chromium-review.googlesource.com/1116550
Reviewed-by: Greg Thompson <grt@chromium.org>
Commit-Queue: Greg Thompson <grt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570717}
[modify] https://crrev.com/16a17d6847498a28b3d5ddb182d5b66adb76e954/third_party/WebKit/LayoutTests/TestExpectations

Test continuous to fail. :-( 

Assigning to test creator.

https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Win7%20Tests%20%281%29/

Failure from layout_tests_results:
--- e:\b\swarm_slave\w\ioh8dlth\layout-test-results\inspector-protocol/animation/animation-multiple-frames-expected.txt
+++ e:\b\swarm_slave\w\ioh8dlth\layout-test-results\inspector-protocol/animation/animation-multiple-frames-actual.txt
@@ -1,14 +1,14 @@
 Tests animation notifications from multiple frames.
+Frame appended
+Animation started: start time is valid
+Frame appended
+Animation started: invalid startTime!47.7539993792772.47.753999912858
 Frame appended
 Animation started: start time is valid
 Frame appended
 Animation started: start time is valid
 Frame appended
-Animation started: start time is valid
-Frame appended
-Animation started: start time is valid
-Frame appended
-Animation started: start time is valid
+Animation started: invalid startTime!84.6959983310699.84.6959989774227
 Frame appended
 Animation started: start time is valid
 Frame appended

Deleted: Screen Shot 2018-07-02 at 5.26.44 PM.png 751 KB

	Screen Shot 2018-07-02 at 5.26.44 PM.png 751 KB View Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/cb297d9bbd8ec3dc6d0789045973e6d95a0c8761

commit cb297d9bbd8ec3dc6d0789045973e6d95a0c8761
Author: Alexei Filippov <alph@chromium.org>
Date: Tue Jul 03 17:19:59 2018

DevTools: Fix rounding error in animation startTime calculations.

The test was flaky because of the rounding errors.

BUG= 856955 

Change-Id: I089ff4efa05935433c6f1cd3a89f8cbad26879d5
Reviewed-on: https://chromium-review.googlesource.com/1123768
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#572265}
[modify] https://crrev.com/cb297d9bbd8ec3dc6d0789045973e6d95a0c8761/third_party/WebKit/LayoutTests/TestExpectations
[modify] https://crrev.com/cb297d9bbd8ec3dc6d0789045973e6d95a0c8761/third_party/WebKit/LayoutTests/inspector-protocol/animation/animation-multiple-frames.js
[modify] https://crrev.com/cb297d9bbd8ec3dc6d0789045973e6d95a0c8761/third_party/blink/renderer/core/inspector/inspector_animation_agent.cc