Build fix for non-X11 and non-ozone builds

The file idle_linux.cc contains some precompiler macro statements for
non-X11 builds which assumes that the macro NOTREACHED from
base/notreached.h is available.

When not building with ozone or X11, this macro is not available. This
CL adds an include for non X11 builds so that builds not using ozone or
X11 succeeds.

Change-Id: I1092e4eb8fcab7c326a6e48ca8890b990d6a652a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2593116Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#837590}

ui/base/idle/idle_linux.cc

@@ -9,6 +9,8 @@
 #if defined(USE_X11)
 #include "ui/base/x/x11_idle_query.h"
 #include "ui/base/x/x11_screensaver_window_finder.h"
+#else
+#include "base/notreached.h"
 #endif
 
 #if defined(USE_OZONE)