[debugger] temporarily re-implement --expose-debug-as.

src/bootstrapper.cc

Index: src/bootstrapper.cc
diff --git a/src/bootstrapper.cc b/src/bootstrapper.cc
index c98a13af179f76e063064d1f83871311078b2651..142d28ec0f191c53be61ed1e23d1fdfe46d968f7 100644
--- a/src/bootstrapper.cc
+++ b/src/bootstrapper.cc
@@ -4196,6 +4196,26 @@ bool Genesis::InstallSpecialObjects(Handle<Context> native_context) {
     WasmJs::Install(isolate);
   }
 
+  // Expose the debug global object in global if a name for it is specified.
+  if (FLAG_expose_debug_as != NULL && strlen(FLAG_expose_debug_as) != 0) {
+    // If loading fails we just bail out without installing the
+    // debugger but without tanking the whole context.
+    Debug* debug = isolate->debug();
+    if (!debug->Load()) return true;
+    Handle<Context> debug_context = debug->debug_context();
+    // Set the security token for the debugger context to the same as
+    // the shell native context to allow calling between these (otherwise
+    // exposing debug global object doesn't make much sense).
+    debug_context->set_security_token(native_context->security_token());
+    Handle<String> debug_string =
+        factory->InternalizeUtf8String(FLAG_expose_debug_as);
+    uint32_t index;
+    if (debug_string->AsArrayIndex(&index)) return true;
+    Handle<Object> global_proxy(debug_context->global_proxy(), isolate);
+    JSObject::AddProperty(handle(native_context->global_proxy()), debug_string,
+                          global_proxy, DONT_ENUM);
+  }
+
   return true;
 }