Adding an api to get number of event listeners.

chrome/test/chromedriver/chrome/event_listener_count.h

Index: chrome/test/chromedriver/chrome/event_listener_count.h
diff --git a/chrome/test/chromedriver/chrome/event_listener_count.h b/chrome/test/chromedriver/chrome/event_listener_count.h
new file mode 100644
index 0000000000000000000000000000000000000000..85756268bfd7d489afc589498cf168728509be57
--- /dev/null
+++ b/chrome/test/chromedriver/chrome/event_listener_count.h
@@ -0,0 +1,37 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_TEST_CHROMEDRIVER_CHROME_EVENT_LISTENER_COUNT_H_
+#define CHROME_TEST_CHROMEDRIVER_CHROME_EVENT_LISTENER_COUNT_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
+#include "chrome/test/chromedriver/chrome/devtools_event_listener.h"
+
+namespace base {
+class DictionaryValue;
+class Value;
+}
+
+class DevToolsClient;
+class Status;
+
+// Take the heap snapshot.
+class EventListenerCount: public DevToolsEventListener {

[chrisgao (Use stgao instead), 2013/10/26 00:54:01]

We don't need to inherit DevToolsEventListener here.
Because the OnConnected/OnEvent/OnCommandSuccess are not overridden, and there
is no need to override them. 

+ public:
+  explicit EventListenerCount(DevToolsClient* client);
+  virtual ~EventListenerCount();
+
+  Status GetEventListenersCount(int *count);
+
+ private:
+  Status GetEventListenersCountInternal(scoped_ptr<base::DictionaryValue>*);
+  DevToolsClient* client_;
+};
+
+#endif  // CHROME_TEST_CHROMEDRIVER_CHROME_EVENT_LISTENER_COUNT_H_
+