Remove use of deprecated base::ListValue::Append(Value*) overload in extensions.

chrome/browser/extensions/api/debugger/debugger_api.cc

Index: chrome/browser/extensions/api/debugger/debugger_api.cc
diff --git a/chrome/browser/extensions/api/debugger/debugger_api.cc b/chrome/browser/extensions/api/debugger/debugger_api.cc
index a64ff5b36bbae2716df31b287e059517c8e3df3d..6242e561ef4bb41a73bc399d57319b696b8d2bf9 100644
--- a/chrome/browser/extensions/api/debugger/debugger_api.cc
+++ b/chrome/browser/extensions/api/debugger/debugger_api.cc
@@ -677,8 +677,10 @@ const char kTargetTabIdField[] = "tabId";
 const char kTargetExtensionIdField[] = "extensionId";
 const char kTargetTypeWorker[] = "worker";
 
-base::Value* SerializeTarget(scoped_refptr<DevToolsAgentHost> host) {
-  base::DictionaryValue* dictionary = new base::DictionaryValue();
+std::unique_ptr<base::DictionaryValue> SerializeTarget(
+    scoped_refptr<DevToolsAgentHost> host) {
+  std::unique_ptr<base::DictionaryValue> dictionary(
+      new base::DictionaryValue());
   dictionary->SetString(kTargetIdField, host->GetId());
   dictionary->SetString(kTargetTitleField, host->GetTitle());
   dictionary->SetBoolean(kTargetAttachedField, host->IsAttached());