Move fileSystem API FilePicker class to own file

chrome/browser/extensions/api/file_system/file_entry_picker.h

+// Copyright 2017 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_EXTENSIONS_API_FILE_SYSTEM_FILE_ENTRY_PICKER_H_
+#define CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_ENTRY_PICKER_H_
+
+#include <vector>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "ui/shell_dialogs/select_file_dialog.h"
+
+namespace base {
+class FilePath;
+}  // namespace base
+
+namespace content {
+class WebContents;
+}  // namespace content
+
+namespace extensions {
+
+// Shows a dialog to the user to ask for the filename for a file to save or
+// open. Deletes itself once the dialog is closed.
+class FileEntryPicker : public ui::SelectFileDialog::Listener {
+ public:
+  using FilesSelectedCallback =
+      base::OnceCallback<void(const std::vector<base::FilePath>& paths)>;

[Devlin, 2017/07/05 19:08:05]

nit: \n

[michaelpg, 2017/07/05 19:52:53]

Done.

+  FileEntryPicker(content::WebContents* web_contents,

[Devlin, 2017/07/05 19:08:05]

Document, either here or above the member variables, what these variables
mean/are used for.

[michaelpg, 2017/07/05 19:52:53]

Done.

+                  const base::FilePath& suggested_name,
+                  const ui::SelectFileDialog::FileTypeInfo& file_type_info,
+                  ui::SelectFileDialog::Type picker_type,
+                  FilesSelectedCallback&& files_selected_callback,

[Devlin, 2017/07/05 19:08:05]

nit: maybe just pass by value here, and std::move it?

[michaelpg, 2017/07/05 19:52:53]

Thanks for catching this. Yeah, what I had goes against the Google style guide
-- callers might forget the function takes an rvalue ref. Passing by value
requires callers to explicitly std::move.

+                  base::OnceClosure&& file_selection_canceled_callback);
+  ~FileEntryPicker() override;

[Devlin, 2017/07/05 19:08:05]

Can we make this private?

[michaelpg, 2017/07/05 19:52:53]

Done (was copied code).

+
+ private:
+  // ui::SelectFileDialog::Listener implementation.
+  void FileSelected(const base::FilePath& path,
+                    int index,
+                    void* params) override;
+

[Devlin, 2017/07/05 19:08:05]

no \n between overridden methods from the same class.

[michaelpg, 2017/07/05 19:52:53]

Done (was copied code)

+  void FileSelectedWithExtraInfo(const ui::SelectedFileInfo& file,
+                                 int index,
+                                 void* params) override;
+
+  void MultiFilesSelected(const std::vector<base::FilePath>& files,
+                          void* params) override;
+
+  void MultiFilesSelectedWithExtraInfo(
+      const std::vector<ui::SelectedFileInfo>& files,
+      void* params) override;
+
+  void FileSelectionCanceled(void* params) override;
+
+  FilesSelectedCallback files_selected_callback_;
+  base::OnceClosure file_selection_canceled_callback_;
+  scoped_refptr<ui::SelectFileDialog> select_file_dialog_;
+
+  DISALLOW_COPY_AND_ASSIGN(FileEntryPicker);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_ENTRY_PICKER_H_