gclient: Support setting local directories as dependency URLs.

Using git daemon for smoke tests times out on Windows.
This CL adds support for local directory URLs to gclient so we can tests
using local directories as remotes instead.

Bug: 1024683
Change-Id: I6dcefa6eb0a93713cf46ea1e4c6b29311ad37565
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/1915416Reviewed-by: Anthony Polito <apolito@google.com>
Commit-Queue: Edward Lesmes <ehmaldonado@chromium.org>

gclient.py

@@ -465,29 +465,46 @@ class Dependency(gclient_utils.WorkItem, DependencySettings):
       logging.info('Dependency(%s)._OverrideUrl(%s) -> %s', self._name,
                    self.url, parsed_url)
       self.set_url(parsed_url)
+      return
+
+    if self.url is None:
+      logging.info('Dependency(%s)._OverrideUrl(None) -> None', self._name)
+      return
 
-    elif isinstance(self.url, basestring):
+    if not isinstance(self.url, basestring):
+      raise gclient_utils.Error('Unknown url type')
+
+    # self.url is a local path
+    path, at, rev = self.url.partition('@')
+    if os.path.isdir(path):
+      return
+
+    # self.url is a URL
     parsed_url = urlparse.urlparse(self.url)
-      if (not parsed_url[0] and
-          not re.match(r'^\w+\@[\w\.-]+\:[\w\/]+', parsed_url[2])):
-        path = parsed_url[2]
+    if parsed_url[0] or re.match(r'^\w+\@[\w\.-]+\:[\w\/]+', parsed_url[2]):
+      return
+
+    # self.url is relative to the parent's URL.
     if not path.startswith('/'):
       raise gclient_utils.Error(
           'relative DEPS entry \'%s\' must begin with a slash' % self.url)
-        # A relative url. Get the parent url, strip from the last '/'
-        # (equivalent to unix basename), and append the relative url.
+
     parent_url = self.parent.url
+    parent_path = self.parent.url.split('@')[0]
+    if os.path.isdir(parent_path):
+      # Parent's URL is a local path. Get parent's URL dirname and append
+      # self.url.
+      parent_path = os.path.dirname(parent_path)
+      parsed_url = parent_path + path.replace('/', os.sep) + at + rev
+    else:
+      # Parent's URL is a URL. Get parent's URL, strip from the last '/'
+      # (equivalent to unix dirname) and append self.url.
       parsed_url = parent_url[:parent_url.rfind('/')] + self.url
+
     logging.info('Dependency(%s)._OverrideUrl(%s) -> %s', self.name,
                  self.url, parsed_url)
     self.set_url(parsed_url)
 
-    elif self.url is None:
-      logging.info('Dependency(%s)._OverrideUrl(None) -> None', self._name)
-
-    else:
-      raise gclient_utils.Error('Unknown url type')
-
   def PinToActualRevision(self):
     """Updates self.url to the revision checked out on disk."""
     if self.url is None: