Move google.cloud.iterator to google.api.core.page_iterator (#3770)

* Move google.cloud.iterator to google.api.core.page_iterator
* Re-write tests to pytest style.
* Make GAXIterator private- it will soon be removed.
* Pass api_request into HTTPIterator to avoid accessing private members
* BigQuery: use google.api.core.page_iterator
* DNS: use google.api.core.page_iterator
* Logging: use google.api.core.page_iterator
* PubSub: use google.api.core.page_iterator
* Resource manager: use google.api.core.page_iterator
* Runtimeconfig: use google.api.core.page_iterator
* logging: use google.api.core._GAXIterator
* Storage: use google.api.core.page_iterator
* Pubsub: use google.api.core._GAXIterator
* Trace: use google.api.core._GAXIterator
* Spanner: use google.api.core._GAXIterator

packages/google-cloud-trace/google/cloud/trace/_gax.py

@@ -14,13 +14,13 @@
 
 """GAX Wrapper for interacting with the Stackdriver Trace API."""
 
+from google.api.core import page_iterator
 from google.cloud.gapic.trace.v1 import trace_service_client
 from google.cloud.proto.devtools.cloudtrace.v1 import trace_pb2
 from google.gax import CallOptions
 from google.gax import INITIAL_PAGE
 from google.cloud._helpers import make_secure_channel
 from google.cloud._http import DEFAULT_USER_AGENT
-from google.cloud.iterator import GAXIterator
 from google.protobuf.json_format import MessageToDict
 from google.protobuf.json_format import ParseDict
 
@@ -131,7 +131,7 @@ def list_traces(
                            passed, the API will return the first page of
                            entries.
 
-        :rtype: :class:`~google.cloud.iterator.Iterator`
+        :rtype: :class:`~google.api.core.page_iterator.Iterator`
         :returns: Traces that match the specified filter conditions.
         """
         if page_token is None:
@@ -147,7 +147,8 @@ def list_traces(
             order_by=order_by,
             options=options)
         item_to_value = _item_to_mapping
-        return GAXIterator(self.client, page_iter, item_to_value)
+        return page_iterator._GAXIterator(
+            self.client, page_iter, item_to_value)
 
 
 def _parse_trace_pb(trace_pb):
@@ -169,7 +170,7 @@ def _parse_trace_pb(trace_pb):
 def _item_to_mapping(iterator, trace_pb):
     """Helper callable function for the GAXIterator
 
-    :type iterator: :class:`~google.cloud.iterator.Iterator`
+    :type iterator: :class:`~google.api.core.page_iterator.Iterator`
     :param iterator: The iterator that is currently in use.
 
     :type trace_pb: :class:`google.cloud.proto.devtools.cloudtrace.v1.

packages/google-cloud-trace/google/cloud/trace/client.py

@@ -144,7 +144,7 @@ def list_traces(
                            passed, the API will return the first page of
                            entries.
 
-        :rtype: :class:`~google.cloud.iterator.Iterator`
+        :rtype: :class:`~google.api.core.page_iterator.Iterator`
         :returns: Traces that match the specified filter conditions.
         """
         if project_id is None: