Update gc branch to bleeding_edge revision 8862.

src/debug.cc

Index: src/debug.cc
diff --git a/src/debug.cc b/src/debug.cc
index d5921175edc6389119c13dbb5d52e83e1fe3396c..adbe70223254978c4ca73ccc9771692fe4b20b8f 100644
--- a/src/debug.cc
+++ b/src/debug.cc
@@ -1969,7 +1969,7 @@ void Debug::AfterGarbageCollection() {
 
 
 Debugger::Debugger(Isolate* isolate)
-    : debugger_access_(OS::CreateMutex()),
+    : debugger_access_(isolate->debugger_access()),
       event_listener_(Handle<Object>()),
       event_listener_data_(Handle<Object>()),
       compiling_natives_(false),
@@ -1991,8 +1991,6 @@ Debugger::Debugger(Isolate* isolate)
 
 
 Debugger::~Debugger() {
-  delete debugger_access_;
-  debugger_access_ = 0;
   delete dispatch_handler_access_;
   dispatch_handler_access_ = 0;
   delete command_received_;