Merge branch 'obtain-token-by-browser' into dev

Author: rayluo

oauth2cli/authcode.py

@@ -5,7 +5,6 @@
 It optionally opens a browser window to guide a human user to manually login.
 After obtaining an auth code, the web server will automatically shut down.
 """
-import webbrowser
 import logging
 import socket
 from string import Template
@@ -35,6 +34,7 @@ def obtain_auth_code(listen_port, auth_uri=None):  # Historically only used in t
 
 
 def _browse(auth_uri):
+    import webbrowser  # Lazy import. Some distro may not have this.
     controller = webbrowser.get()  # Get a default controller
     # Some Linux Distro does not setup default browser properly,
     # so we try to explicitly use some popular browser, if we found any.