Disable flaky WebViewFocusBrowserPluginSpecificTest.TouchFocusesEmbedder.

The test is extremely flaky on Linux.

Bug: 870604
Change-Id: I02242da7c685075ce148a6f302b67afe1b5804a4
TBR: lazyboy@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/1161921Reviewed-by: Balazs Engedy <engedy@chromium.org>
Commit-Queue: Balazs Engedy <engedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580498}

chrome/browser/apps/guest_view/web_view_browsertest.cc

@@ -4352,10 +4352,17 @@ class WebViewFocusBrowserPluginSpecificTest
   }
 };
 
+// Flaky on Linux. See: https://crbug.com/870604.
+#if defined(OS_LINUX)
+#define MAYBE_TouchFocusesEmbedder DISABLED_TouchFocusesEmbedder
+#else
+#define MAYBE_TouchFocusesEmbedder TouchFocusesEmbedder
+#endif
+
 // The following test verifies that a views::WebView hosting an embedder
 // gains focus on touchstart.
 IN_PROC_BROWSER_TEST_F(WebViewFocusBrowserPluginSpecificTest,
-                       TouchFocusesEmbedder) {
+                       MAYBE_TouchFocusesEmbedder) {
   LoadAppWithGuest("web_view/accept_touch_events");
 
   content::WebContents* web_contents = GetEmbedderWebContents();