Adds the ability to run pure Go unit tests in the Mojo test suite.

mojo/tools/mopy/paths.py

 # 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.
 
 import os
 
 from .config import Config
 from .gn import BuildDirectoryForConfig
 
 class Paths(object):
   """Provides commonly used paths"""
 
   def __init__(self, config=None, build_dir=None):
     """Specify either a config or a build_dir to generate paths to binary
     artifacts."""
     self.src_root = os.path.abspath(os.path.join(__file__,
       os.pardir, os.pardir, os.pardir, os.pardir))
     self.mojo_dir = os.path.join(self.src_root, "mojo")
     self.adb_path = os.path.join(self.src_root, 'third_party', 'android_tools',
                                  'sdk', 'platform-tools', 'adb')
 
+    self.go_tool_path = None
+    if config:
+      if (config.target_os == Config.OS_LINUX and
+          config.target_cpu == Config.ARCH_X64):
+        self.go_tool_path = os.path.join(self.src_root, "third_party",
+            "go", "tool", "linux_amd64", "bin", "go")
+      elif config.target_os == Config.OS_ANDROID:
+        self.go_tool_path = os.path.join(self.src_root, "third_party",
+            "go", "tool", "android_arm", "bin", "go")
+
     if config:
       self.build_dir = BuildDirectoryForConfig(config, self.src_root)
     elif build_dir is not None:
       self.build_dir = os.path.abspath(build_dir)
     else:
       self.build_dir = None
 
     if self.build_dir is not None:
       self.mojo_shell_path = os.path.join(self.build_dir, "mojo_shell")
       self.dart_snapshotter_path = os.path.join(
@@ skipping 45 matching lines @@
       return os.path.join(self.build_dir, name + '.mojo')
     return name + '.mojo'
 
   @staticmethod
   def IsValidAppUrl(url):
     """Returns False if url is malformed, True otherwise."""
     try:
       return len(url.split(':')) == 2
     except ValueError:
       return False