Fix gn gen for ipc_message_lib under use_ozone=true

Broken at 4ec75161

The busted FYI bot build is:
https://build.chromium.org/p/chromium.gpu.fyi/builders/Linux%20ChromiumOS%20Ozone%20Builder/builds/27173

TBR=mbarbella@chromium.org

Change-Id: If4cad6ae90bab1c6ae12d65d568fbda8975ef50c
Reviewed-on: https://chromium-review.googlesource.com/598453
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491555}

tools/ipc_fuzzer/ipc_fuzzer.gni

@@ -5,6 +5,7 @@
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/sanitizers/sanitizers.gni")
+import("//build/config/ui.gni")
 
 declare_args() {
   # Build IPC fuzzer by default if it's a supported configuration. For
@@ -12,5 +13,5 @@ declare_args() {
   # (especially MSan).
   enable_ipc_fuzzer =
       is_clang && !is_component_build && !is_official_build && !is_chromecast &&
-      !using_sanitizer && (is_linux || is_mac || is_win)
+      !using_sanitizer && (is_linux || is_mac || is_win) && !use_ozone
 }