[cr tool] Adding the main function and remaining pieces.

tools/cr/cr/autocomplete.py

Index: tools/cr/cr/autocomplete.py
diff --git a/tools/cr/cr/autocomplete.py b/tools/cr/cr/autocomplete.py
new file mode 100644
index 0000000000000000000000000000000000000000..3a0fba0c14bcc1d2afd3139d6caa8a27cd3a04a5
--- /dev/null
+++ b/tools/cr/cr/autocomplete.py
@@ -0,0 +1,27 @@
+# Copyright (c) 2013 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.
+
+"""Bash auto completion support.
+
+Contains the special mode that returns lists of possible completions for the
+current command line.
+"""
+
+import cr
+
+
+def Complete(context):
+  """Attempts to build a completion list for the current command line.
+
+  COMP_WORD contains the word that is being completed, and COMP_CWORD has

[bulach, 2013/11/14 16:40:16]

I think COMP_WORD usage will show up later on? maybe best to remove from here,
wdyt?

[ian_cottrell, 2013/11/15 10:28:51]

I thought it was worth documenting because it's part of the formal contract
between cr.sh and main.py, it is effectively a parameter of this function, but
passed in a global, an ugly but necessary evil of the completion to bash to
python flow.

+  the index of that word on the command line.
+
+  Args:
+    context: The cr context object, of type cr.context.Context.
+  """
+
+  _ = context
+  # TODO(iancottrell): support auto complete of more than just the command
+  # try to parse the command line using parser
+  print ' '.join(command.name for command in cr.Command.Plugins())