Introduce Application Default Credentials concept
Replace the 'Default Credentials' concept with the 'Application Default Credentials' concept.
diff --git a/googleapiclient/discovery.py b/googleapiclient/discovery.py
index 6385ea9..e01386c 100644
--- a/googleapiclient/discovery.py
+++ b/googleapiclient/discovery.py
@@ -260,11 +260,11 @@
# If credentials were passed in, we could have two cases:
# 1. the scopes were specified, in which case the given credentials
# are used for authorizing the http;
- # 2. the scopes were not provided (meaning the Default Credentials are
- # to be used). In this case, the Default Credentials are built and
- # used instead of the original credentials. If there are no scopes
- # found (meaning the given service requires no authentication), there is
- # no authorization of the http.
+ # 2. the scopes were not provided (meaning the Application Default
+ # Credentials are to be used). In this case, the Application Default
+ # Credentials are built and used instead of the original credentials.
+ # If there are no scopes found (meaning the given service requires no
+ # authentication), there is no authorization of the http.
if (isinstance(credentials, GoogleCredentials) and
credentials.create_scoped_required()):
scopes = service.get('auth', {}).get('oauth2', {}).get('scopes', {})