Use std::unique_ptr<base::Value> in V8ValueConverter.

extensions/renderer/script_injection.cc

 // Copyright 2014 The Chromium 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 "extensions/renderer/script_injection.h"
 
 #include <map>
 #include <utility>
 
 #include "base/lazy_instance.h"
@@ skipping 274 matching lines @@
     if (!results.isEmpty() && !results[0].IsEmpty()) {
       // Right now, we only support returning single results (per frame).
       std::unique_ptr<content::V8ValueConverter> v8_converter(
           content::V8ValueConverter::create());
       // It's safe to always use the main world context when converting
       // here. V8ValueConverterImpl shouldn't actually care about the
       // context scope, and it switches to v8::Object's creation context
       // when encountered.
       v8::Local<v8::Context> context =
           render_frame_->GetWebFrame()->mainWorldScriptContext();
-      execution_result_.reset(v8_converter->FromV8Value(results[0], context));
+      execution_result_ = v8_converter->FromV8Value(results[0], context);
     }
     if (!execution_result_.get())
       execution_result_ = base::Value::CreateNullValue();
   }
   did_inject_js_ = true;
 
   // If |async_completion_callback_| is set, it means the script finished
   // asynchronously, and we should run it.
   if (!async_completion_callback_.is_null()) {
     injector_->OnInjectionComplete(std::move(execution_result_), run_location_,
                                    render_frame_);
     // Warning: this object can be destroyed after this line!
     async_completion_callback_.Run(this);
   }
 }
 
 void ScriptInjection::InjectCss() {
   std::vector<std::string> css_sources =
       injector_->GetCssSources(run_location_);
   blink::WebLocalFrame* web_frame = render_frame_->GetWebFrame();
   for (const std::string& css : css_sources)
     web_frame->document().insertStyleSheet(blink::WebString::fromUTF8(css));
 }
 
 }  // namespace extensions