Improve error handling of the transport security state generator.

net/tools/transport_security_state_generator/preloaded_state_generator.h

Index: net/tools/transport_security_state_generator/preloaded_state_generator.h
diff --git a/net/tools/transport_security_state_generator/preloaded_state_generator.h b/net/tools/transport_security_state_generator/preloaded_state_generator.h
index 562c4f38ead297ff708d356b45a4399568cb1dad..f6b157315bf0f16bb82d0ad009977227a7344027 100644
--- a/net/tools/transport_security_state_generator/preloaded_state_generator.h
+++ b/net/tools/transport_security_state_generator/preloaded_state_generator.h
@@ -28,11 +28,11 @@ class PreloadedStateGenerator {
   PreloadedStateGenerator();
   ~PreloadedStateGenerator();
 
+  // Returns the generated C++ code on success and the empty string on failure.
   std::string Generate(const std::string& preload_template,
                        const TransportSecurityStateEntries& entries,
                        const DomainIDList& domain_ids,
-                       const Pinsets& pinsets,
-                       bool verbose);
+                       const Pinsets& pinsets);
 
  private:
   // TODO(Martijnc): Remove the domain IDs from the preload format.