[serializer/debugger] hide scripts in the snapshot from the debugger.

src/snapshot/startup-serializer.cc

 // Copyright 2016 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/snapshot/startup-serializer.h"
 
 #include "src/objects-inl.h"
 #include "src/v8threads.h"
 
 namespace v8 {
@@ skipping 55 matching lines @@
   if (SerializeBackReference(obj, how_to_code, where_to_point, skip)) return;
 
   FlushSkip(skip);
 
   if (isolate_->external_reference_redirector() && obj->IsAccessorInfo()) {
     // Wipe external reference redirects in the accessor info.
     AccessorInfo* info = AccessorInfo::cast(obj);
     Address original_address = Foreign::cast(info->getter())->foreign_address();
     Foreign::cast(info->js_getter())->set_foreign_address(original_address);
     accessor_infos_.Add(info);
+  } else if (obj->IsScript() && Script::cast(obj)->IsUserJavaScript()) {
+    // Reset type for user scripts embedded in the start-up snapshot to hide
+    // them from the debugger.
+    Script::cast(obj)->set_type(Script::TYPE_EXTENSION);
   }
 
   // Object has not yet been serialized.  Serialize it here.
   ObjectSerializer object_serializer(this, obj, &sink_, how_to_code,
                                      where_to_point);
   object_serializer.Serialize();
 
   if (serializing_immortal_immovables_roots_ &&
       root_index != RootIndexMap::kInvalidRootIndex) {
     // Make sure that the immortal immovable root has been included in the first
@@ skipping 93 matching lines @@
   if (root_index == Heap::kStackLimitRootIndex ||
       root_index == Heap::kRealStackLimitRootIndex) {
     return true;
   }
   return Heap::RootIsImmortalImmovable(root_index) !=
          serializing_immortal_immovables_roots_;
 }
 
 }  // namespace internal
 }  // namespace v8