Remove unused debug API.

src/debug.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "v8.h"
 
 #include "api.h"
 #include "arguments.h"
 #include "bootstrapper.h"
 #include "code-stubs.h"
@@ skipping 2846 matching lines @@
     CallJSEventCallback(event, exec_state, event_data);
   }
 }
 
 
 void Debug::CallCEventCallback(v8::DebugEvent event,
                                Handle<Object> exec_state,
                                Handle<Object> event_data,
                                v8::Debug::ClientData* client_data) {
   Handle<Foreign> callback_obj(Handle<Foreign>::cast(event_listener_));
-  v8::Debug::EventCallback2 callback =
-      FUNCTION_CAST<v8::Debug::EventCallback2>(
+  v8::Debug::EventCallback callback =
+      FUNCTION_CAST<v8::Debug::EventCallback>(
           callback_obj->foreign_address());
   EventDetailsImpl event_details(
       event,
       Handle<JSObject>::cast(exec_state),
       Handle<JSObject>::cast(event_data),
       event_listener_data_,
       client_data);
   callback(event_details);
 }
 
@@ skipping 583 matching lines @@
   logger_->DebugEvent("Put", message.text());
 }
 
 
 void LockingCommandMessageQueue::Clear() {
   LockGuard<Mutex> lock_guard(&mutex_);
   queue_.Clear();
 }
 
 } }  // namespace v8::internal