Moving scripts to download and build apprtc/collider.

We are starting to move code to setup our tests from [1].
We are moving only scripts to download and build apprtc, collider and node
(scripts that work on firefox have not been copied by this CL).

[1] - https://chromium.googlesource.com/chromium/deps/webrtc/webrtc.DEPS/

BUG=webrtc:7602
NOTRY=True

Review-Url: https://codereview.webrtc.org/2861653005
Cr-Commit-Position: refs/heads/master@{#18060}

webrtc/tools/testing/build_apprtc_collider.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python
+# Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+"""Builds the AppRTC collider using the golang toolchain.
+
+The golang toolchain is downloaded by download_golang.py. We use that here
+to build the AppRTC collider server.
+
+This script needs to know the path to the 'src' directory in apprtc, the
+root directory of 'go', the root directory of 'hg' and the output_dir.
+"""
+
+import os
+import shutil
+import subprocess
+import sys
+
+import utils
+
+
+USAGE_STR = "Usage: {} <apprtc_src_dir> <go_dir> <hg_dir> <output_dir>"
+
+
+def main(argv):
+  if len(argv) != 5:
+    return USAGE_STR.format(argv[0])
+
+  apprtc_dir = argv[1]
+  go_root_dir = argv[2]
+  mercurial_dir = argv[3]
+  golang_workspace = argv[4]
+
+  utils.RemoveDirectory(golang_workspace)
+
+  golang_workspace_src = os.path.join(golang_workspace, 'src')
+
+  collider_dir = os.path.join(apprtc_dir, 'collider')
+  shutil.copytree(collider_dir, golang_workspace_src,
+                  ignore=shutil.ignore_patterns('.svn', '.git'))
+
+  golang_binary = 'go%s' % ('.exe' if utils.GetPlatform() == 'win' else '')
+  golang_path = os.path.join(go_root_dir, 'bin', golang_binary)
+
+  golang_env = os.environ.copy()
+  golang_env['GOROOT'] = go_root_dir
+  golang_env['GOPATH'] = os.path.abspath(golang_workspace)
+  golang_env['PATH'] += os.pathsep + mercurial_dir
+  subprocess.check_call([golang_path, 'get', 'collidermain'],
+                        env=golang_env)
+  collider_exec = os.path.join(golang_workspace, 'collidermain')
+  subprocess.check_call([golang_path, 'build', '-o', collider_exec,
+                         'collidermain'], env=golang_env)
+
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv))