GN: fix up //media/base linux dependencies

media/base/user_input_monitor_linux.cc depends on //ui/gfx/x and
//ui/events:events_base

Review URL: https://codereview.chromium.org/547533006

Cr-Commit-Position: refs/heads/master@{#293669}

media/base/BUILD.gn

@@ -195,6 +195,10 @@ source_set("base") {
   #         "//build/config/linux:xtst",
     ]
     sources += [ "user_input_monitor_linux.cc" ]
+    deps += [
+      "//ui/events:events_base",
+      "//ui/gfx/x",
+    ]
   } else if (is_mac) {
     sources += [ "user_input_monitor_mac.cc" ]
   } else if (is_win) {