Separate gfx_ipc into skia-dependent and non-skia-dependent parts

ui/gfx/ipc/skia/gfx_ipc_skia.gyp

+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+{
+  'variables': {
+    'chromium_code': 1,
+  },
+  'targets': [
+    {
+      # GN version: //ui/gfx/ipc/skia
+      'target_name': 'gfx_ipc_skia',
+      'type': '<(component)',
+      'dependencies': [
+        '../../../../base/base.gyp:base',
+        '../../../../ipc/ipc.gyp:ipc',
+        '../../../../skia/skia.gyp:skia',
+        '../../gfx.gyp:gfx',
+        '../../gfx.gyp:gfx_geometry',
+        '../gfx_ipc.gyp:gfx_ipc',
+      ],
+      'defines': [
+        'GFX_SKIA_IPC_IMPLEMENTATION',
+      ],
+      'include_dirs': [
+        '../../../..',
+      ],
+      'sources': [
+        'gfx_skia_param_traits.cc',
+        'gfx_skia_param_traits.h',
+      ],
+    },
+  ],
+}