[mus] Disable badly flaking apptest

components/mus/ws/window_manager_client_apptest.cc

Index: components/mus/ws/window_manager_client_apptest.cc
diff --git a/components/mus/ws/window_manager_client_apptest.cc b/components/mus/ws/window_manager_client_apptest.cc
index b3da12c227bbfdea1309f31e92e262d96898600a..fe3cc179752e84760729c5401a18458cb578f0be 100644
--- a/components/mus/ws/window_manager_client_apptest.cc
+++ b/components/mus/ws/window_manager_client_apptest.cc
@@ -845,7 +845,8 @@ TEST_F(WindowServerTest, Activation) {
             ValidIndexOf(parent->children(), child1));
 }
 
-TEST_F(WindowServerTest, ActivationNext) {
+// Very flaky: http://crbug.com/592313.
+TEST_F(WindowServerTest, DISABLED_ActivationNext) {
   Window* parent = GetFirstWMRoot();
   Window* child1 = NewVisibleWindow(parent, window_manager());
   Window* child2 = NewVisibleWindow(parent, window_manager());