Ad Exchange Buyer API v1 code samples.

Reviewed in http://codereview.appspot.com/5711045/.

Index: samples/adexchangebuyer/client_secrets.json
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diff --git a/samples/adexchangebuyer/update_account.py b/samples/adexchangebuyer/update_account.py
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+#!/usr/bin/python
+#
+# Copyright 2012 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""This example illustrates how to do a sparse update of the account attributes.
+
+Tags: accounts.patch
+"""
+
+__author__ = 'david.t@google.com (David Torres)'
+
+import pprint
+import sys
+import gflags
+from oauth2client.client import AccessTokenRefreshError
+import sample_utils
+
+# Declare command-line flags, and set them as required.
+gflags.DEFINE_string('account_id', None,
+                     'The ID of the account to which submit the creative',
+                     short_name='a')
+gflags.MarkFlagAsRequired('account_id')
+gflags.DEFINE_string('cookie_matching_url', None,
+                     'New cookie matching URL to set for the account ',
+                     short_name='u')
+gflags.MarkFlagAsRequired('cookie_matching_url')
+
+
+def main(argv):
+  sample_utils.process_flags(argv)
+  account_id = gflags.FLAGS.account_id
+  cookie_matching_url = gflags.FLAGS.cookie_matching_url
+  pretty_printer = pprint.PrettyPrinter()
+
+  # Authenticate and construct service.
+  service = sample_utils.initialize_service()
+
+  try:
+    # Account information to be updated.
+    account_body = {
+        'accountId': account_id,
+        'cookieMatchingUrl': cookie_matching_url
+        }
+    account = service.accounts().patch(id=account_id,
+                                       body=account_body).execute()
+    pretty_printer.pprint(account)
+  except AccessTokenRefreshError:
+    print ('The credentials have been revoked or expired, please re-run the '
+           'application to re-authorize')
+
+if __name__ == '__main__':
+  main(sys.argv)