[Cronet] Use prebuilt Netty Http/2 server for Cronet BidirectionalStream testing.

third_party/netty/netty.gyp

+# Copyright (c) 2010 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': [
+    { # These targets require prebuilt binaries for netty and libnetty_tcnative.
+      # Ask mef@ for their location.
+      'target_name': 'netty_all',
+      'type' : 'none',
+      'variables': {
+        'jar_path': 'android/netty-all-4.1.0.CR1-20151123.120819-12.jar',
+        'exclude_from_apk': 1,
+      },
+      'includes': ['../../build/java_prebuilt.gypi'],
+    },
+    {
+      'target_name': 'netty_tcnative',
+      'type' : 'none',
+      'variables': {
+        'jar_path': 'android/libnetty_tcnative.jar',
+        'exclude_from_apk': 1,
+      },
+      'includes': ['../../build/java_prebuilt.gypi'],
+      'copies': [
+        {
+          'destination': '<(PRODUCT_DIR)',
+          'files': [
+            'android/libnetty-tcnative.so',
+          ],
+        },
+      ],
+    },
+  ],
+}