[Extensions] Reduce string copy in renderer/ UserScript.

extensions/renderer/dispatcher.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/dispatcher.h"
 
 #include <stddef.h>
 
 #include <memory>
 #include <utility>
@@ skipping 564 matching lines @@
     // we insert the default platform app or extension stylesheet into all
     // documents that are loaded in each app or extension.
     frame->document().insertStyleSheet(WebString::fromUTF8(stylesheet));
   }
 
   // If this is an extension options page, and the extension has opted into
   // using Chrome styles, then insert the Chrome extension stylesheet.
   if (extension && extension->is_extension() &&
       OptionsPageInfo::ShouldUseChromeStyle(extension) &&
       effective_document_url == OptionsPageInfo::GetOptionsPage(extension)) {
+    base::StringPiece extension_css =
+        ResourceBundle::GetSharedInstance().GetRawDataResource(
+            IDR_EXTENSION_CSS);
     frame->document().insertStyleSheet(
-        WebString::fromUTF8(ResourceBundle::GetSharedInstance()
-                                .GetRawDataResource(IDR_EXTENSION_CSS)
-                                .as_string()));
+        WebString::fromUTF8(extension_css.data(), extension_css.length()));
   }
 
   // In testing, the document lifetime events can happen after the render
   // process shutdown event.
   // See: http://crbug.com/21508 and http://crbug.com/500851
   if (content_watcher_) {
     content_watcher_->DidCreateDocumentElement(frame);
   }
 }
 
@@ skipping 1068 matching lines @@
   // The "guestViewDeny" module must always be loaded last. It registers
   // error-providing custom elements for the GuestView types that are not
   // available, and thus all of those types must have been checked and loaded
   // (or not loaded) beforehand.
   if (context_type == Feature::BLESSED_EXTENSION_CONTEXT) {
     module_system->Require("guestViewDeny");
   }
 }
 
 }  // namespace extensions