Add synchronization around access when using ReloadLocaleResources

ui/base/resource/resource_bundle.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 "ui/base/resource/resource_bundle.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/file_util.h"
@@ skipping 145 matching lines @@
     if (command_line->HasSwitch(switches::kLocalePak)) {
       locale_file_path =
           command_line->GetSwitchValuePath(switches::kLocalePak);
     } else {
       locale_file_path = GetLocaleFilePath(app_locale);
     }
   }
 
   if (locale_file_path.empty()) {
     // It's possible that there is no locale.pak.
+    DLOG(WARNING) << "locale_file_path.empty()";
     return std::string();
   }
 
   scoped_ptr<DataPack> data_pack(
       new DataPack(SCALE_FACTOR_100P));
   if (!data_pack->Load(locale_file_path)) {
     UMA_HISTOGRAM_ENUMERATION("ResourceBundle.LoadLocaleResourcesError",
                               logging::GetLastSystemErrorCode(), 16000);
     NOTREACHED() << "failed to load locale.pak";
     return std::string();
@@ skipping 120 matching lines @@
 }
 
 base::StringPiece ResourceBundle::GetRawDataResource(
     int resource_id,
     ScaleFactor scale_factor) const {
   base::StringPiece data;
   if (delegate_ &&
       delegate_->GetRawDataResource(resource_id, scale_factor, &data))
     return data;
 
+  // TODO(tony): Firm up locking for or constraints of calling
+  // ReloadLocaleResources() and how to CHECK for misuse.
   DCHECK(locale_resources_data_.get());
   if (locale_resources_data_->GetStringPiece(resource_id, &data))
     return data;
 
   if (scale_factor != ui::SCALE_FACTOR_100P) {
     for (size_t i = 0; i < data_packs_.size(); i++) {
       if (data_packs_[i]->GetScaleFactor() == scale_factor &&
           data_packs_[i]->GetStringPiece(resource_id, &data))
         return data;
     }
@@ skipping 177 matching lines @@
     SkBitmap bitmap;
     bitmap.setConfig(SkBitmap::kARGB_8888_Config, 32, 32);
     bitmap.allocPixels();
     bitmap.eraseARGB(255, 255, 0, 0);
     empty_image_ = gfx::Image(bitmap);
   }
   return empty_image_;
 }
 
 }  // namespace ui