Allow steps to fail with error message

Summary:
Add a method to add error messages into failed steps. This will be surfaced in the diagnostic screen, to help the user
troubleshoot.

Reviewed By: passy

Differential Revision: D9333322

fbshipit-source-id: 5f1e55c3d71b19292dbc428aaecfbd41e7a75125

xplat/Sonar/SonarStep.h

@@ -15,11 +15,12 @@ class SonarState;
 class SonarStep {
  public:
   void complete();
+  void fail(std::string message);
   SonarStep(std::string name, SonarState* state);
   ~SonarStep();
 
  private:
   std::string name;
-  bool isCompleted = false;
+  bool isLogged = false;
   SonarState* state;
 };