Add support for long-poll HTTP request at /privet/v3/checkForUpdates

Added state/command definition notification mechanism through a long
poll HTTP request as described in:
https://developers.google.com/cloud-devices/v1/reference/local-api/check_for_updates

BUG: 23908251
Change-Id: I5285403f35f23a310404d3324a7a255b77211264
Reviewed-on: https://weave-review.googlesource.com/1533
Reviewed-by: Vitaly Buka <vitalybuka@google.com>
diff --git a/src/privet/mock_delegates.h b/src/privet/mock_delegates.h
index 755110e..2186f2f 100644
--- a/src/privet/mock_delegates.h
+++ b/src/privet/mock_delegates.h
@@ -45,8 +45,10 @@
   MOCK_CONST_METHOD0(GetHttpEnpoint, IntPair());
   MOCK_CONST_METHOD0(GetHttpsEnpoint, IntPair());
   MOCK_CONST_METHOD0(GetUptime, base::TimeDelta());
-  MOCK_METHOD1(SetHttpPort, void(uint16_t));
-  MOCK_METHOD1(SetHttpsPort, void(uint16_t));
+  MOCK_CONST_METHOD0(GetHttpRequestTimeout, base::TimeDelta());
+  MOCK_METHOD3(PostDelayedTask, void(const tracked_objects::Location&,
+                                     const base::Closure&,
+                                     base::TimeDelta));
 
   MockDeviceDelegate() {
     EXPECT_CALL(*this, GetHttpEnpoint())