Disable SingleProcessBrowserTest.Test on ChromeOS.

We're not supporting in-process network service on ChromeOS for now.

Bug: 927435
Change-Id: I88f4e62ac1534c88cf77635fa6b8c4ac5464397e
Reviewed-on: https://chromium-review.googlesource.com/c/1449109
Commit-Queue: Robbie McElrath <rmcelrath@chromium.org>
Commit-Queue: John Abd-El-Malek <jam@chromium.org>
Auto-Submit: Robbie McElrath <rmcelrath@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628176}

chrome/test/base/in_process_browser_test_browsertest.cc

@@ -97,7 +97,9 @@ IN_PROC_BROWSER_TEST_F(InProcessBrowserTest, AfterStartupTaskUtils) {
 
 // On Mac this crashes inside cc::SingleThreadProxy::SetNeedsCommit. See
 // https://ci.chromium.org/b/8923336499994443392
-#if !defined(OS_MACOSX)
+// On ChromeOS this crashes because ProfileIOData and NetworkContext both try
+// to set up NSS on different threads, which it doesn't like.
+#if !defined(OS_MACOSX) && !defined(OS_CHROMEOS)
 class SingleProcessBrowserTest : public InProcessBrowserTest {
  public:
   void SetUpCommandLine(base::CommandLine* command_line) override {