Abort sync cycles when download step fails

sync/test/engine/mock_connection_manager.h

Index: sync/test/engine/mock_connection_manager.h
diff --git a/sync/test/engine/mock_connection_manager.h b/sync/test/engine/mock_connection_manager.h
index a2b50601c76441c5b63e1bbc93470154688149ac..5cc1b87258c2516dbc0b14f7eecca12ef83c5e32 100644
--- a/sync/test/engine/mock_connection_manager.h
+++ b/sync/test/engine/mock_connection_manager.h
@@ -117,7 +117,8 @@ class MockConnectionManager : public browser_sync::ServerConnectionManager {
   // issue multiple requests during a sync cycle.
   void NextUpdateBatch();
 
-  void FailNextPostBufferToPathCall() { fail_next_postbuffer_ = true; }

[rlarocque, 2012/04/06 20:35:09]

At this point, it probably makes sense to start thinking about using gmock here.
 However, I'd rather just get my current CL done for now and we can revisit the
entire class in a later CL.

+  void FailNextPostBufferToPathCall() { countdown_to_postbuffer_fail_ = 1; }
+  void FailNthPostBufferToPathCall(int n) { countdown_to_postbuffer_fail_ = n; }
 
   void SetClearUserDataResponseStatus(sync_pb::SyncEnums::ErrorType errortype);
 
@@ -222,6 +223,11 @@ class MockConnectionManager : public browser_sync::ServerConnectionManager {
     return store_birthday_;
   }
 
+  // Explicitly indicate that we will not be fetching some updates.
+  void ClearUpdatesQueue() {
+    update_queue_.clear();
+  }
+
   // Locate the most recent update message for purpose of alteration.
   sync_pb::SyncEntity* GetMutableLastUpdate();
 
@@ -299,8 +305,9 @@ class MockConnectionManager : public browser_sync::ServerConnectionManager {
   bool client_stuck_;
   std::string commit_time_rename_prepended_string_;
 
-  // Fail on the next call to PostBufferToPath().
-  bool fail_next_postbuffer_;
+  // On each PostBufferToPath() call, we decrement this counter.  The call fails
+  // iff we hit zero at that call.
+  int countdown_to_postbuffer_fail_;
 
   // Our directory.  Used only to ensure that we are not holding the transaction
   // lock when performing network I/O.  Can be NULL if the test author is