Mark http/tests/devtools/oopif/oopif-performance-cpu-profiles.js as flaky

NOTRY=true
TBR=kpaulhamus@chromium.org
BUG=848398

Change-Id: I6d769cc2fd3d9bc393b6320387fc7a43a630473a
Reviewed-on: https://chromium-review.googlesource.com/1081493Reviewed-by: Kim Paulhamus <kpaulhamus@chromium.org>
Reviewed-by: Alexei Filippov <alph@chromium.org>
Commit-Queue: Alexei Filippov <alph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#563403}

third_party/WebKit/LayoutTests/TestExpectations

@@ -4822,4 +4822,5 @@ crbug.com/847373 [ Mac Linux ] virtual/pwa-full-code-cache/http/tests/devtools/s
 # Sheriff 2018-05-31
 crbug.com/848258 [ Win7 ] fast/gradients/unprefixed-repeating-linear-gradient.html [ Failure ]
 crbug.com/848281 [ Linux ] http/tests/security/cross-origin-session-storage-allowed.html [ Failure ]
-crbug.com/848354 [ Linux ] plugins/fullscreen-plugins-dont-reload.html [ Skip ]
+crbug.com/848354 [ Linux ] plugins/fullscreen-plugins-dont-reload.html [ Skip ]
\ No newline at end of file
+crbug.com/848398 [ Linux Mac ] http/tests/devtools/oopif/oopif-performance-cpu-profiles.js [ Pass Timeout Failure ]