Revert of Remove SVN and File support from gclient (patchset #4 id:60001 of...

Revert of Remove SVN and File support from gclient (patchset #4 id:60001 of https://codereview.chromium.org/2398493004/ )

Reason for revert:
The Chrome buildbots pass "--transitive" still. Removing the option causes them to fail to build.

Example:

https://uberchromegw.corp.google.com/i/chromeos.chrome/builders/x86-alex-tot-chrome-pfq-informational/builds/21555

Original issue's description:
> Remove SVN and File support from gclient
>
> FileImpl was only usable with SVN.
>
> R=maruel@chromium.org
> BUG=641588
>
> Committed: https://chromium.googlesource.com/chromium/tools/depot_tools/+/b3a24c3fd5159972f58063967a9c07ef724ff97b

TBR=maruel@chromium.org,agable@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=641588

Review-Url: https://codereview.chromium.org/2405173003

gclient_scm.py

@@ -392,6 +392,14 @@ class GitWrapper(SCMWrapper):
     if managed:
       self._DisableHooks()
 
+    if gclient_utils.IsDateRevision(revision):
+      # Date-revisions only work on git-repositories if the reflog hasn't
+      # expired yet. Use rev-list to get the corresponding revision.
+      #  git rev-list -n 1 --before='time-stamp' branchname
+      if options.transitive:
+        self.Print('Warning: --transitive only works for SVN repositories.')
+        revision = default_rev
+
     rev_str = ' at %s' % revision
     files = [] if file_list is not None else None
 
@@ -1484,6 +1492,12 @@ class SVNWrapper(SCMWrapper):
                 self.Print('You can pass --force to enable automatic removal.')
               raise e
 
+    # Retrieve the current HEAD version because svn is slow at null updates.
+    if options.manually_grab_svn_rev and not revision:
+      from_info_live = scm.SVN.CaptureRemoteInfo(from_info['URL'])
+      revision = str(from_info_live['Revision'])
+      rev_str = ' at %s' % revision
+
     if from_info['URL'].rstrip('/') != base_url.rstrip('/'):
       # The repository url changed, need to switch.
       try:
@@ -1713,6 +1727,10 @@ class SVNWrapper(SCMWrapper):
       new_command.append('--force')
       if command[0] != 'checkout' and scm.SVN.AssertVersion('1.6')[0]:
         new_command.extend(('--accept', 'theirs-conflict'))
+    elif options.manually_grab_svn_rev:
+      new_command.append('--force')
+      if command[0] != 'checkout' and scm.SVN.AssertVersion('1.6')[0]:
+        new_command.extend(('--accept', 'postpone'))
     elif command[0] != 'checkout' and scm.SVN.AssertVersion('1.6')[0]:
       new_command.extend(('--accept', 'postpone'))
     return new_command

tests/gclient_test.py

@@ -244,13 +244,17 @@ class GclientTest(trial_dir.TestCase):
           obj.dependencies[0], 'foo/dir2',
           gclient.GClientKeywords.FromImpl('bar'), None, None, None, None,
           None, 'DEPS', True, False),
+        gclient.Dependency(
+          obj.dependencies[0], 'foo/dir3',
+          gclient.GClientKeywords.FileImpl('url'), None, None, None, None,
+          None, 'DEPS', True, False),
       ],
       [])
     # Make sure __str__() works fine.
     # pylint: disable=W0212
     obj.dependencies[0]._file_list.append('foo')
     str_obj = str(obj)
-    self.assertEquals(370, len(str_obj), '%d\n%s' % (len(str_obj), str_obj))
+    self.assertEquals(471, len(str_obj), '%d\n%s' % (len(str_obj), str_obj))
 
   def testHooks(self):
     topdir = self.root_dir