Add formula for a libangle third_party cache

Formula/libangle-deps@4844.rb

@@ -0,0 +1,29 @@
+class LibangleDepsAT4844 < Formula
+  desc "Third party dependencies for Libangle"
+  homepage "https://github.com/google/angle"
+  url "https://github.com/google/angle.git", using: :git, revision: "29b222a3c07c541cafa459ae6886134da3493a4b"
+  version "4844.29b222a"
+  license "Various"
+
+  depends_on "meson" => :build
+  depends_on "ninja" => :build
+  depends_on "depot-tools" => :build
+
+  keg_only :versioned_formula
+
+  def install
+    system "python3", "scripts/bootstrap.py"
+    system "gclient", "sync"
+
+    dst = prefix/'deps'
+    dst.mkpath unless dst.directory?
+
+    %w[.cipd .gclient .gclient_entries build buildtools testing third_party tools].each do |f|
+      mv f, dst
+    end
+  end
+
+  test do
+    system "true"
+  end
+end