[Extensions] rm unnecessary GetRawDataResource().as_string() to reduce string copy.

chrome/browser/ui/webui/extensions/extension_icon_source.cc

 // Copyright (c) 2012 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 "chrome/browser/ui/webui/extensions/extension_icon_source.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 79 matching lines @@
                                    extension->id().c_str(),
                                    icon_size,
                                    match,
                                    grayscale ? "?grayscale=true" : ""));
   CHECK(icon_url.is_valid());
   return icon_url;
 }
 
 // static
 SkBitmap* ExtensionIconSource::LoadImageByResourceId(int resource_id) {
-  std::string contents = ResourceBundle::GetSharedInstance()
-      .GetRawDataResourceForScale(resource_id,
-                                  ui::SCALE_FACTOR_100P).as_string();
+  base::StringPiece contents =
+      ResourceBundle::GetSharedInstance().GetRawDataResourceForScale(
+          resource_id, ui::SCALE_FACTOR_100P);
 
   // Convert and return it.
   const unsigned char* data =
       reinterpret_cast<const unsigned char*>(contents.data());
   return ToBitmap(data, contents.length());
 }
 
 std::string ExtensionIconSource::GetSource() const {
   return chrome::kChromeUIExtensionIconHost;
 }
@@ skipping 230 matching lines @@
   std::map<int, ExtensionIconRequest*>::iterator i =
       request_map_.find(request_id);
   if (i == request_map_.end())
     return;
 
   delete i->second;
   request_map_.erase(i);
 }
 
 }  // namespace extensions