Mark inspector/elements/iframe-load-event.html as flaky

BUG=493815
[email protected]

Review URL: https://codereview.chromium.org/1154593007

git-svn-id: svn://svn.chromium.org/blink/trunk@196164 bbb929c8-8fbe-4397-9dbb-9b2b20218538
diff --git a/third_party/WebKit/LayoutTests/TestExpectations b/third_party/WebKit/LayoutTests/TestExpectations
index fe4cb19c..cb3301fe 100644
--- a/third_party/WebKit/LayoutTests/TestExpectations
+++ b/third_party/WebKit/LayoutTests/TestExpectations
@@ -1739,3 +1739,5 @@
 
 # Temporary, until [Unforgeable] attributes have the right accessors 'get' and 'set'.
 crbug.com/491006 http/tests/security/cross-origin-access-over-property-descriptor.html [ Failure ]
+
+crbug.com/493815 inspector/elements/iframe-load-event.html [ Pass Failure ]