Implement configurable stats reporting

SYN-287

This requires that HS owners either opt in or out of stats reporting.

When --generate-config is passed, --report-stats must be specified
If an already-generated config is used, and doesn't have the
report_stats key, it is requested to be set.

tests/storage/event_injector.py

@@ -0,0 +1,81 @@
+# -*- coding: utf-8 -*-
+# Copyright 2015 OpenMarket Ltd
+#
+# 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.
+
+
+from tests import unittest
+from twisted.internet import defer
+
+from synapse.api.constants import EventTypes, Membership
+from synapse.types import UserID, RoomID
+
+from tests.utils import setup_test_homeserver
+
+from mock import Mock
+
+
+class EventInjector:
+    def __init__(self, hs):
+        self.hs = hs
+        self.store = hs.get_datastore()
+        self.message_handler = hs.get_handlers().message_handler
+        self.event_builder_factory = hs.get_event_builder_factory()
+
+    @defer.inlineCallbacks
+    def create_room(self, room):
+        builder = self.event_builder_factory.new({
+            "type": EventTypes.Create,
+            "room_id": room.to_string(),
+            "content": {},
+        })
+
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
+        )
+
+        yield self.store.persist_event(event, context)
+
+    @defer.inlineCallbacks
+    def inject_room_member(self, room, user, membership):
+        builder = self.event_builder_factory.new({
+            "type": EventTypes.Member,
+            "sender": user.to_string(),
+            "state_key": user.to_string(),
+            "room_id": room.to_string(),
+            "content": {"membership": membership},
+        })
+
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
+        )
+
+        yield self.store.persist_event(event, context)
+
+        defer.returnValue(event)
+
+    @defer.inlineCallbacks
+    def inject_message(self, room, user, body):
+        builder = self.event_builder_factory.new({
+            "type": EventTypes.Message,
+            "sender": user.to_string(),
+            "state_key": user.to_string(),
+            "room_id": room.to_string(),
+            "content": {"body": body, "msgtype": u"message"},
+        })
+
+        event, context = yield self.message_handler._create_new_client_event(
+            builder
+        )
+
+        yield self.store.persist_event(event, context)