diff --git a/telemetry/telemetry/core/chrome/inspector_timeline_unittest.py b/telemetry/telemetry/core/chrome/inspector_timeline_unittest.py
index <HASH>..<HASH> 100644
--- a/telemetry/telemetry/core/chrome/inspector_timeline_unittest.py
+++ b/telemetry/telemetry/core/chrome/inspector_timeline_unittest.py
@@ -24,7 +24,11 @@ class InspectorTimelineTabTest(tab_test_case.TabTestCase):
       self._tab.ExecuteJavaScript(
 """
 var done = false;
-window.webkitRequestAnimationFrame(function() { done = true; });
+function sleep(ms) {
+  var endTime = (new Date().getTime()) + ms;
+  while ((new Date().getTime()) < endTime);
+}
+window.webkitRequestAnimationFrame(function() { sleep(10); done = true; });
 """)
       self._WaitForAnimationFrame()
[Telemetry] Fix InspectorTimelineTabTest.testGotTimeline on windows.

It was asserting that the duration of the event was 0. To fix this, we sleep
for <I>ms in the RAF event.

BUG=<I>
TEST=python tools\telemetry\run_tests InspectorTimelineTabTest.testGotTimeline
NOTRY=True

Review URL: <URL>