Disable the PrerenderBrowserTest.PageLoadMetricsPrerender test.

chrome/browser/prerender/prerender_browsertest.cc

Index: chrome/browser/prerender/prerender_browsertest.cc
diff --git a/chrome/browser/prerender/prerender_browsertest.cc b/chrome/browser/prerender/prerender_browsertest.cc
index 97faf45a3528b75d28b964d868efbfc54c837a31..88349192885dbb73d6155cd750fd7567705e0ee3 100644
--- a/chrome/browser/prerender/prerender_browsertest.cc
+++ b/chrome/browser/prerender/prerender_browsertest.cc
@@ -1092,7 +1092,13 @@ IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PageLoadMetricsSimple) {
 
 // Checks that the correct page load metrics observers are produced with a
 // prerender.
-IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, PageLoadMetricsPrerender) {
+// TODO(https://crbug.com/678976) Fails on ChromeOS and Linux.
+#if defined(OS_CHROMEOS) || defined(OS_LINUX)
+#define MAYBE_PageLoadMetricsPrerender DISABLED_PageLoadMetricsPrerender
+#else
+#define MAYBE_PageLoadMetricsPrerender PageLoadMetricsPrerender
+#endif
+IN_PROC_BROWSER_TEST_F(PrerenderBrowserTest, MAYBE_PageLoadMetricsPrerender) {
   test_utils::FirstContentfulPaintManagerWaiter* prerender_fcp_waiter =
       test_utils::FirstContentfulPaintManagerWaiter::Create(
           GetPrerenderManager());