Add Robolectric build and license files to third_party.

third_party/robolectric/robolectric.gyp

Index: third_party/robolectric/robolectric.gyp
diff --git a/third_party/robolectric/robolectric.gyp b/third_party/robolectric/robolectric.gyp
new file mode 100644
index 0000000000000000000000000000000000000000..831267221d57a5857c52630d16b928b88b31061b
--- /dev/null
+++ b/third_party/robolectric/robolectric.gyp
@@ -0,0 +1,34 @@
+# 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.
+
+{
+  'targets': [
+    {
+      # GN: //third_party/robolectric:android_all_java
+      'target_name': 'android_all_jar',
+      'type': 'none',
+      'variables': {
+        'jar_path': 'lib/android-all-5.0.0_r2-robolectric-0.jar',
+      },
+      'includes': [
+        '../../build/host_prebuilt_jar.gypi',
+      ]
+    },
+    {
+      # GN: //third_party/robolectric:robolectric_prebuilt_java
+      'target_name': 'robolectric_prebuilt_jar',
+      'type': 'none',
+      'dependencies': [
+        'android_all_jar',
+      ],
+      'variables': {
+        'jar_path': 'lib/robolectric-2.4-jar-with-dependencies.jar',
+      },
+      'includes': [
+        '../../build/host_prebuilt_jar.gypi',
+      ]
+    },
+  ],
+}
+