Disable SerialTest.NavigateWithChooserCrossOrigin on OS_CHROMEOS

This should be OS_CHROMEOS, not OS_LINUX.

TBR=reillyg@chromium.org

Bug: 1069695
Change-Id: Ib1c3e42ee0110fca5a14d256ca00db2ff737a5ae
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2303032Reviewed-by: Kristi Park <kristipark@chromium.org>
Reviewed-by: Noel Gordon <noel@chromium.org>
Commit-Queue: Kristi Park <kristipark@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Auto-Submit: Kristi Park <kristipark@chromium.org>
Cr-Commit-Position: refs/heads/master@{#789133}

chrome/browser/serial/chrome_serial_browsertest.cc

@@ -53,7 +53,7 @@ class SerialTest : public InProcessBrowserTest {
 };
 
 // TODO(crbug/1069695): Flaky on linux-chromeos-chrome.
-#if defined(OS_LINUX)
+#if defined(OS_CHROMEOS)
 #define MAYBE_NavigateWithChooserCrossOrigin \
   DISABLED_NavigateWithChooserCrossOrigin
 #else