CLN: remove pandas/io/gbq.py and tests and replace with pandas-gbq

closes #15347

Author: jreback

ci/requirements-2.7.pip

@@ -1,8 +1,5 @@
 blosc
-httplib2
-google-api-python-client==1.2
-python-gflags==2.0
-oauth2client==1.5.0
+pandas-gbq
 pathlib
 backports.lzma
 py

ci/requirements-3.4.pip

@@ -1,5 +1,2 @@
 python-dateutil==2.2
 blosc
-httplib2
-google-api-python-client
-oauth2client

ci/requirements-3.4_SLOW.pip

@@ -1 +1,2 @@
 xarray==0.9.1
+pandas-gbq

ci/requirements-3.5.pip

@@ -4652,6 +4652,13 @@ And then issue the following queries:
 Google BigQuery
 ---------------
 
+.. warning::
+
+   Starting in 0.20.0, pandas has split off Google BigQuery support into the
+   separate package ``pandas-gbq``. You can ``pip install pandas-gbq`` to get it.
+
+   Documentation is now hosted `here <https://pandas-gbq.readthedocs.io/>`__
+
 .. versionadded:: 0.13.0
 
 The :mod:`pandas.io.gbq` module provides a wrapper for Google's BigQuery

doc/source/io.rst

@@ -360,6 +360,15 @@ New Behavior:
   In [5]: df['a']['2011-12-31 23:59:59']
   Out[5]: 1
 
+.. _whatsnew_0200.api_breaking.gbq:
+
+Pandas Google BigQuery support has moved
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+pandas has split off Google BigQuery support into a separate package ``pandas-gbq``. You can ``pip install pandas-gbq`` to get it.
+The functionaility of ``pd.read_gbq()`` and ``.to_gbq()`` remains the same with the currently released version of ``pandas-gbq=0.1.2``. (:issue:`15347`)
+Documentation is now hosted `here <https://pandas-gbq.readthedocs.io/>`__
+
 .. _whatsnew_0200.api_breaking.memory_usage:
 
 Memory Usage for Index is more Accurate

doc/source/whatsnew/v0.20.0.txt

@@ -77,7 +77,8 @@
                            OrderedDict, raise_with_traceback)
 from pandas import compat
 from pandas.compat.numpy import function as nv
-from pandas.util.decorators import deprecate_kwarg, Appender, Substitution
+from pandas.util.decorators import (deprecate_kwarg, Appender,
+                                    Substitution, docstring_wrapper)
 from pandas.util.validators import validate_bool_kwarg
 
 from pandas.tseries.period import PeriodIndex
@@ -903,6 +904,7 @@ def to_dict(self, orient='dict'):
         else:
             raise ValueError("orient '%s' not understood" % orient)
 
+    @docstring_wrapper(lambda: pandas.io.gbq._try_import().to_gbq.__doc__)
     def to_gbq(self, destination_table, project_id, chunksize=10000,
                verbose=True, reauth=False, if_exists='fail', private_key=None):
         """Write a DataFrame to a Google BigQuery table.