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

R=jgruber@chromium.org
BUG=v8:6274

Review-Url: https://codereview.chromium.org/2826073004
Cr-Commit-Position: refs/heads/master@{#44745}

src/debug/debug.cc

@@ -2059,13 +2059,13 @@ void Debug::OnAsyncTaskEvent(debug::PromiseDebugActionType type, int id,
 }
 
 void Debug::ProcessCompileEvent(v8::DebugEvent event, Handle<Script> script) {
+  if (!script->IsUserJavaScript() && script->type() != i::Script::TYPE_WASM) {
+    return;
+  }
   // Attach the correct debug id to the script. The debug id is used by the
   // inspector to filter scripts by native context.
   script->set_context_data(isolate_->native_context()->debug_context_id());
   if (ignore_events()) return;
-  if (!script->IsUserJavaScript() && script->type() != i::Script::TYPE_WASM) {
-    return;
-  }
   if (!debug_delegate_) return;
   SuppressDebug while_processing(this);
   DebugScope debug_scope(this);

src/snapshot/startup-serializer.cc

@@ -73,6 +73,10 @@ void StartupSerializer::SerializeObject(HeapObject* obj, HowToCode how_to_code,
     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.

test/cctest/test-serialize.cc

@@ -638,6 +638,11 @@ TEST(CustomSnapshotDataBlob1) {
         CompileRun("f()")->Int32Value(isolate1->GetCurrentContext());
     CHECK_EQ(42, result.FromJust());
     CHECK(CompileRun("this.g")->IsUndefined());
+    v8::Local<v8::Value> f = CompileRun("f");
+    i::Handle<i::JSFunction> function =
+        i::Handle<i::JSFunction>::cast(v8::Utils::OpenHandle(*f));
+    // Being part of the snapshot hides a script from the debugger.
+    CHECK(!function->shared()->IsSubjectToDebugging());
   }
   isolate1->Dispose();
 }