GN: Make content_shell and webkit_unit_tests work in component build

content/gpu/BUILD.gn

Index: content/gpu/BUILD.gn
diff --git a/content/gpu/BUILD.gn b/content/gpu/BUILD.gn
index 02f0de67a28f1d5fd974773e9e2e5e6a94429efc..e8e39fefae7902eea342ae5c0eb5fe64ae700e30 100644
--- a/content/gpu/BUILD.gn
+++ b/content/gpu/BUILD.gn
@@ -2,6 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/ui.gni")
 import("//content/content.gni")
 
 # We don't support x64 prior to Win7 and D3DCompiler_43.dll is not needed on
@@ -51,6 +52,10 @@ source_set("gpu") {
   if (is_chromeos && cpu_arch != "arm") {
     configs += [ "//third_party/libva/libva_config" ]
   }
+
+  if (use_x11) {
+    deps += [ "//ui/events/platform/x11" ]
+  }
 }
 
 if (need_d3dcompiler) {