Extend DebugAgent API with AsyncDebugRunner

include/v8-debug.h

Index: include/v8-debug.h
diff --git a/include/v8-debug.h b/include/v8-debug.h
index b27bacc1080123b11f6a93c3302147aac3013b0d..58458db209c9bbc108164cee281efc96fd1fa514 100644
--- a/include/v8-debug.h
+++ b/include/v8-debug.h
@@ -80,6 +80,18 @@ enum DebugEvent {
 };
 
 
+/**
+ * Function helps debug agent to start V8 whenever there are debug requests
+ * pending. This makes V8 responsive to remote debugger even when no script
+ * is being running.
+ * Should cause an empty cycle to be run in V8 (e.g. evaluate "void(0)")
+ * either synchronously or asynchronously.
+ * Should return false if embedder for some reason is not going to start V8
+ * in any reasonable future.
+ */
+typedef bool (*AsyncDebugRunner)();
+
+
 class EXPORT Debug {
  public:
   /**
@@ -258,8 +270,10 @@ class EXPORT Debug {
   * supplied TCP/IP port for remote debugger connection.
   * \param name the name of the embedding application
   * \param port the TCP/IP port to listen on
+  * \param debug_runner helps V8 respond when idle; may be NULL
   */
-  static bool EnableAgent(const char* name, int port);
+  static bool EnableAgent(const char* name, int port,
+                          AsyncDebugRunner async_debug_runner = NULL);
 };