Add ANGLE build overrides.

This will allow ANGLE to use Chromium repos for third_party deps.

Bug: angleproject:3088
Change-Id: I0d8d4c53df780d59fdc97813fb468d0960b18def
Reviewed-on: https://chromium-review.googlesource.com/c/1424397
Reviewed-by: John Budorick <jbudorick@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#625340}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 27e844933cdcd563923c0eda3b3a8df3b1866bbe
diff --git a/angle.gni b/angle.gni
new file mode 100644
index 0000000..56b6c8e
--- /dev/null
+++ b/angle.gni
@@ -0,0 +1,10 @@
+# Copyright 2019 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.
+
+# Overrides for ANGLE's dependencies
+angle_glslang_dir = "//third_party/glslang/src"
+angle_googletest_dir = "//third_party/googletest/src"
+angle_jsoncpp_dir = "//third_party/jsoncpp"
+angle_libpng_dir = "//third_party/libpng"
+angle_spirv_tools_dir = "//third_party/SPIRV-Tools/src"