[Extensions] Convert some ChromeSyncExtensionFunctions

chrome/browser/chromeos/extensions/file_system_provider/provider_function.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_SYSTEM_PROVIDER_PROVIDER_FUNCTION_H_
 #define CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_SYSTEM_PROVIDER_PROVIDER_FUNCTION_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 32 matching lines @@
 // These values are passed to JavaScript as lastError.message value.
 std::string FileErrorToString(base::File::Error error);
 
 // Converts ProviderError to base::File::Error. This could be redundant, if it
 // was possible to create DOMError instances in Javascript easily.
 base::File::Error ProviderErrorToFileError(
     api::file_system_provider::ProviderError error);
 
 // Base class for internal API functions handling request results, either
 // a success or a failure.
-class FileSystemProviderInternalFunction : public ChromeSyncExtensionFunction {
+class FileSystemProviderInternalFunction : public UIThreadExtensionFunction {
  public:
   FileSystemProviderInternalFunction();
 
  protected:
   ~FileSystemProviderInternalFunction() override {}
 
-  // Rejects the request and sets a response for this API function. Returns true
-  // on success, and false on failure.
-  bool RejectRequest(
+  // Rejects the request and returns a response for this API function.
+  ResponseAction RejectRequest(
       std::unique_ptr<chromeos::file_system_provider::RequestValue> value,
       base::File::Error error);
 
   // Fulfills the request with parsed arguments of this API function
-  // encapsulated as a RequestValue instance. Also, sets a response.
+  // encapsulated as a RequestValue instance and returns a response.
   // If |has_more| is set to true, then the function will be called again for
-  // this request. Returns true on success, and false on failure.
-  bool FulfillRequest(
+  // this request.
+  ResponseAction FulfillRequest(
       std::unique_ptr<chromeos::file_system_provider::RequestValue> value,
       bool has_more);
 
-  // Subclasses implement this for their functionality.
-  // Called after Parse() is successful, such that |request_id_| and
-  // |request_manager_| have been fully initialized.
-  virtual bool RunWhenValid() = 0;
-
-  // ChromeSyncExtensionFunction overrides.
-  bool RunSync() override;
-
  private:
-  // Parses the request in order to extract the request manager. If fails, then
-  // sets a response and returns false.
-  bool Parse();
+  // Guarantees |request_id_| and |request_manager_| are valid.
+  bool PreRunValidation(std::string* error) override;
 
   int request_id_;
   chromeos::file_system_provider::RequestManager* request_manager_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_CHROMEOS_EXTENSIONS_FILE_SYSTEM_PROVIDER_PROVIDER_FUNCTION_H_