buffet: Allow setting command results.

Next step in command results support: now there is
CommandInstance::SetResults method which allows results
modifications.

BUG=chromium:435607
TEST=cros_workon_make --test buffet

Change-Id: I1f5da9c3613a2996cea3f65f07945cc64bfeda2e
Reviewed-on: https://chromium-review.googlesource.com/231337
Reviewed-by: Alex Vakulenko <avakulenko@chromium.org>
Tested-by: Anton Muhin <antonm@chromium.org>
Commit-Queue: Anton Muhin <antonm@chromium.org>

buffet/commands/cloud_command_proxy.h

diff --git a/buffet/commands/cloud_command_proxy.h b/buffet/commands/cloud_command_proxy.h
index 0c35c0c..e78ff44 100644
--- a/buffet/commands/cloud_command_proxy.h
+++ b/buffet/commands/cloud_command_proxy.h
@@ -24,6 +24,7 @@
   ~CloudCommandProxy() override = default;
 
   // CommandProxyInterface implementation/overloads.
+  void OnResultsChanged(const native_types::Object& results) override;
   void OnStatusChanged(const std::string& status) override;
   void OnProgressChanged(int progress) override;