Accompany debugger commands with senders data

src/debug-agent.cc

Index: src/debug-agent.cc
===================================================================
--- src/debug-agent.cc	(revision 1753)
+++ src/debug-agent.cc	(working copy)
@@ -35,10 +35,12 @@
 // Public V8 debugger API message handler function. This function just delegates
 // to the debugger agent through it's data parameter.
 void DebuggerAgentMessageHandler(const uint16_t* message, int length,
-                                 void *data) {
-  reinterpret_cast<DebuggerAgent*>(data)->DebuggerMessage(message, length);
+                                 v8::Debug::ClientData* client_data) {
+  DebuggerAgent::instance_->DebuggerMessage(message, length);
 }
 
+// static
+DebuggerAgent* DebuggerAgent::instance_ = NULL;
 
 // Debugger agent main thread.
 void DebuggerAgent::Run() {