Remove more usage of the base::ListValue::Append(Value*) overload.

content/renderer/devtools/devtools_agent.cc

Index: content/renderer/devtools/devtools_agent.cc
diff --git a/content/renderer/devtools/devtools_agent.cc b/content/renderer/devtools/devtools_agent.cc
index 0016d880d0b49c1bb4df7c51528afb174423c29a..0e4c56b2f5ff4ee1eb18e2746fa2ed08c47cbe3d 100644
--- a/content/renderer/devtools/devtools_agent.cc
+++ b/content/renderer/devtools/devtools_agent.cc
@@ -327,14 +327,15 @@ void DevToolsAgent::GotManifest(int session_id,
 
   bool failed = false;
   for (const auto& error : debug_info.errors) {
-    base::DictionaryValue* error_value = new base::DictionaryValue();
-    errors->Append(error_value);
+    std::unique_ptr<base::DictionaryValue> error_value(
+        new base::DictionaryValue());
     error_value->SetString("message", error.message);
     error_value->SetBoolean("critical", error.critical);
     error_value->SetInteger("line", error.line);
     error_value->SetInteger("column", error.column);
     if (error.critical)
       failed = true;
+    errors->Append(std::move(error_value));
   }
 
   WebString url = frame_->GetWebFrame()->document().manifestURL().string();