Expose arguments and options to handlers through JSONStream

runtime/vm/json_stream.h

Index: runtime/vm/json_stream.h
diff --git a/runtime/vm/json_stream.h b/runtime/vm/json_stream.h
index 8afea7a56e7871fe3820a2ce96b6fc00eb31aa7a..79b1c69eb1b350769ea8c001a460d8de48f34f56 100644
--- a/runtime/vm/json_stream.h
+++ b/runtime/vm/json_stream.h
@@ -39,12 +39,33 @@ class JSONStream : ValueObject {
       PRINTF_ATTRIBUTE(3, 4);
   void PrintProperty(const char* name, const Object& o, bool ref = true);
 
+  void SetArguments(const char** arguments, intptr_t num_arguments);
+  void SetOptions(const char** option_keys, const char** option_values,
+                  intptr_t num_options);
+
+  intptr_t num_arguments() const { return num_arguments_; }
+  const char* GetArgument(intptr_t i) const {
+    return arguments_[i];
+  }
+  intptr_t num_options() const { return num_options_; }
+  const char* GetOptionKey(intptr_t i) const {
+    return option_keys_[i];
+  }
+  const char* GetOptionValue(intptr_t i) const {
+    return option_values_[i];
+  }
+
  private:
   void PrintPropertyName(const char* name);
   void PrintCommaIfNeeded();
   bool NeedComma();
   intptr_t open_objects_;
   TextBuffer* buffer_;
+  const char** arguments_;
+  intptr_t num_arguments_;
+  const char** option_keys_;
+  const char** option_values_;
+  intptr_t num_options_;
 };
 
 }  // namespace dart