Disable DevToolsExtensionTest.ExtensionWebSocketUserAgentOverride on ChromeOS

TBR=gayane@chromium.org
NOTRY=true

Bug: 971241
Change-Id: I373aa360faa185ff15ff940fea5dd622b376d86d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1645160Reviewed-by: Xida Chen <xidachen@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#666273}

chrome/browser/devtools/devtools_sanity_browsertest.cc

@@ -2395,6 +2395,14 @@ IN_PROC_BROWSER_TEST_F(SitePerProcessDevToolsSanityTest,
   DevToolsWindowTesting::CloseDevToolsWindowSync(window);
 }
 
+// Fail on chrome os. See https://crbug.com/971241
+#if defined(OS_CHROMEOS)
+#define MAYBE_ExtensionWebSocketUserAgentOverride \
+  DISABLED_ExtensionWebSocketUserAgentOverride
+#else
+#define MAYBE_ExtensionWebSocketUserAgentOverride \
+  ExtensionWebSocketUserAgentOverride
+#endif
 IN_PROC_BROWSER_TEST_F(DevToolsExtensionTest,
                        ExtensionWebSocketUserAgentOverride) {
   net::SpawnedTestServer websocket_server(