Remove some UI->FILE->UI thread hops in ExecuteCodeFunction

extensions/browser/api/execute_code_function.h

 // Copyright (c) 2013 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.
 
 #ifndef EXTENSIONS_BROWSER_API_EXECUTE_CODE_FUNCTION_H_
 #define EXTENSIONS_BROWSER_API_EXECUTE_CODE_FUNCTION_H_
 
 #include "base/macros.h"
 #include "extensions/browser/extension_function.h"
 #include "extensions/browser/script_executor.h"
@@ skipping 34 matching lines @@
                               bool success,
                               std::unique_ptr<std::string> data);
 
   const HostID& host_id() const { return host_id_; }
   void set_host_id(const HostID& host_id) { host_id_ = host_id; }
 
   // The injection details.
   std::unique_ptr<api::extension_types::InjectDetails> details_;
 
  private:
-  // Called when contents from the file whose path is specified in JSON
-  // arguments has been loaded.
-  void DidLoadFile(bool success, std::unique_ptr<std::string> data);
+  // Retrieves the file url for the given |extension_path| and optionally
+  // localizes |data|.
+  // Localization depends on whether |might_require_localization| was specified.
+  // Only CSS file content needs to be localized.
+  void GetFileURLAndMaybeLocalizeOnFileThread(
+      const std::string& extension_id,
+      const base::FilePath& extension_path,
+      const std::string& extension_default_locale,
+      bool might_require_localization,
+      std::string* data);
 
-  // Runs on FILE thread. Loads message bundles for the extension and
-  // localizes the CSS data. Calls back DidLoadAndLocalizeFile on the UI thread.
-  void GetFileURLAndLocalizeCSS(ScriptExecutor::ScriptType script_type,
-                                std::unique_ptr<std::string> data,
-                                const std::string& extension_id,
-                                const base::FilePath& extension_path,
-                                const std::string& extension_default_locale);
+  void GetFileURLAndLocalizeComponentResourceOnFileThread(

[Devlin, 2016/09/01 06:15:21]

nit: a brief comment documenting this would be good.

[lazyboy, 2016/09/01 18:10:18]

Done.

+      std::unique_ptr<std::string> data,
+      bool might_require_localization,
+      const std::string& extension_id,
+      const base::FilePath& extension_path,
+      const std::string& extension_default_locale);
 
   // Run in UI thread.  Code string contains the code to be executed. Returns
   // true on success. If true is returned, this does an AddRef.
   bool Execute(const std::string& code_string);
 
   // Contains extension resource built from path of file which is
   // specified in JSON arguments.
   ExtensionResource resource_;
 
   // The URL of the file being injected into the page.
   GURL file_url_;
 
   // The ID of the injection host.
   HostID host_id_;
 
   DISALLOW_COPY_AND_ASSIGN(ExecuteCodeFunction);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_EXECUTE_CODE_FUNCTION_H_