code: public Type resolve(String fullyQualifiedName) {
          Type local = symbolTable.get(fullyQualifiedName);
          if (local != null) {
              return local;
          }
          for (ProtoContext importedContext : publicImports) {
              Type imported = importedContext.resolve(fullyQualifiedName);
              if (imported != null) {
                  return imported;
              }
          }
          for (ProtoContext importedContext : imports) {
              Type imported = importedContext.resolveImport(fullyQualifiedName);
              if (imported != null) {
                  return imported;
              }
          }
          return null;
      }
docs: Resolve a type declaration by it's fully-qualified name
  using this proto context.