Move chrome.fileSystem implementation to //extensions

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

 // 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.
 
 #include "chrome/browser/extensions/api/file_system/file_entry_picker.h"
 
 #include <memory>
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/string16.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/ui/chrome_select_file_policy.h"
 #include "content/public/browser/web_contents.h"
+#include "extensions/browser/api/file_system/file_system_delegate.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/shell_dialogs/selected_file_info.h"
 
 namespace extensions {
 
 FileEntryPicker::FileEntryPicker(
     content::WebContents* web_contents,
     const base::FilePath& suggested_name,
     const ui::SelectFileDialog::FileTypeInfo& file_type_info,
     ui::SelectFileDialog::Type picker_type,
-    FilesSelectedCallback files_selected_callback,
+    FileSystemDelegate::FilesSelectedCallback files_selected_callback,
     base::OnceClosure file_selection_canceled_callback)
     : files_selected_callback_(std::move(files_selected_callback)),
       file_selection_canceled_callback_(
           std::move(file_selection_canceled_callback)) {
   CHECK(web_contents);
   gfx::NativeWindow owning_window =
       platform_util::GetTopLevel(web_contents->GetNativeView());
   select_file_dialog_ = ui::SelectFileDialog::Create(
       this, base::MakeUnique<ChromeSelectFilePolicy>(web_contents).release());
   select_file_dialog_->SelectFile(
@@ skipping 39 matching lines @@
     paths.push_back(file.file_path);
   MultiFilesSelected(paths, params);
 }
 
 void FileEntryPicker::FileSelectionCanceled(void* params) {
   std::move(file_selection_canceled_callback_).Run();
   delete this;
 }
 
 }  // namespace extensions