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

src/bootstrapper.cc

 // Copyright 2014 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 "src/bootstrapper.h"
 
 #include "src/accessors.h"
 #include "src/api-natives.h"
 #include "src/base/ieee754.h"
 #include "src/code-stubs.h"
@@ skipping 4178 matching lines @@
   Handle<JSObject> Error = isolate->error_function();
   Handle<String> name =
       factory->InternalizeOneByteString(STATIC_CHAR_VECTOR("stackTraceLimit"));
   Handle<Smi> stack_trace_limit(Smi::FromInt(FLAG_stack_trace_limit), isolate);
   JSObject::AddProperty(Error, name, stack_trace_limit, NONE);
 
   if (FLAG_expose_wasm || FLAG_validate_asm) {
     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;
 }
 
 
 static uint32_t Hash(RegisteredExtension* extension) {
   return v8::internal::ComputePointerHash(extension);
 }
 
 Genesis::ExtensionStates::ExtensionStates() : map_(8) {}
 
@@ skipping 569 matching lines @@
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   DCHECK(!IsActive());
 }
 
 }  // namespace internal
 }  // namespace v8