Begin converting blink_skia_config from gyp to gypi.

public/blink_skia_config.gypi

+# Copyright 2014 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': {
+
+    # Place defines here that require significant Blink rebaselining, or that
+    # are otherwise best removed in Blink and then rolled into Chromium.
+    # Defines should be in single quotes and a comma must appear after every one.
+    # DO NOT remove the define until you are ready to rebaseline, and
+    # AFTER the flag has been removed from skia.gyp in Chromium.
+    'blink_skia_defines': [
+    ],
+  },
+}