Gardening: Mark http/tests/serviceworker/fetch.html as slow on Win7

NOTRY=true
TBR=arv@chromium.org
BUG=411779

Review URL: https://codereview.chromium.org/546633008

git-svn-id: svn://svn.chromium.org/blink/trunk@181540 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/LayoutTests/TestExpectations

@@ -1159,6 +1159,8 @@ crbug.com/30536 [ Win ] http/tests/xmlhttprequest/origin-exact-matching/29.html
 crbug.com/30536 [ Win ] http/tests/xmlhttprequest/origin-exact-matching/30.html [ Failure ]
 crbug.com/30536 [ Win ] http/tests/xmlhttprequest/origin-exact-matching/36.html [ Failure ]
 
+crbug.com/411779 [ Win7 ] http/tests/serviceworker/fetch.html [ Slow ]
+
 # switching to apache-win32 flakiness that needs triaging.
 crbug.com/30536 [ Win ] http/tests/htmlimports/import-cors-credentials.html [ Timeout Pass ]
 crbug.com/30536 [ Win ] http/tests/htmlimports/redirect-cross-origin.html [ Timeout Pass ]