[extension SW]: Support event listener registration and event dispatching.

extensions/renderer/event_bindings.h

Index: extensions/renderer/event_bindings.h
diff --git a/extensions/renderer/event_bindings.h b/extensions/renderer/event_bindings.h
index f2d1ad77a72c5a5de7b5afb0b0e1a7b6dee7e7e8..72bb7f6d6674468ad0131414a37faed8f6817810 100644
--- a/extensions/renderer/event_bindings.h
+++ b/extensions/renderer/event_bindings.h
@@ -13,6 +13,10 @@
 #include "extensions/renderer/object_backed_native_handler.h"
 #include "v8/include/v8.h"
 
+namespace IPC {
+class Sender;
+}
+
 namespace base {
 class DictionaryValue;
 }
@@ -73,6 +77,8 @@ class EventBindings : public ObjectBackedNativeHandler {
   std::unique_ptr<EventMatcher> ParseEventMatcher(
       std::unique_ptr<base::DictionaryValue> filter);
 
+  IPC::Sender* GetIPCSender();
+
   // Called when our context, and therefore us, is invalidated. Run any cleanup.
   void OnInvalidated();