alloy: Fix crash when downloading a modified PDF form (see issue #3169)

Create a CefFileSystemDelegate based on the ShellFileSystemDelegate placeholder
implementation. An actual implementation will still be required to properly
support this download functionality.

libcef/browser/extensions/api/file_system/cef_file_system_delegate.cc

@@ -0,0 +1,71 @@
+// 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 "libcef/browser/extensions/api/file_system/cef_file_system_delegate.h"
+
+#include "apps/saved_files_service.h"
+#include "base/callback.h"
+#include "base/callback_forward.h"
+#include "base/files/file_path.h"
+#include "extensions/common/api/file_system.h"
+#include "extensions/common/extension.h"
+
+namespace extensions {
+namespace cef {
+
+CefFileSystemDelegate::CefFileSystemDelegate() = default;
+
+CefFileSystemDelegate::~CefFileSystemDelegate() = default;
+
+base::FilePath CefFileSystemDelegate::GetDefaultDirectory() {
+  return base::FilePath();
+}
+
+base::FilePath CefFileSystemDelegate::GetManagedSaveAsDirectory(
+    content::BrowserContext* browser_context,
+    const Extension& extension) {
+  return base::FilePath();
+}
+
+bool CefFileSystemDelegate::ShowSelectFileDialog(
+    scoped_refptr<ExtensionFunction> extension_function,
+    ui::SelectFileDialog::Type type,
+    const base::FilePath& default_path,
+    const ui::SelectFileDialog::FileTypeInfo* file_types,
+    FileSystemDelegate::FilesSelectedCallback files_selected_callback,
+    base::OnceClosure file_selection_canceled_callback) {
+  NOTIMPLEMENTED();
+
+  // Run the cancel callback by default.
+  std::move(file_selection_canceled_callback).Run();
+
+  // Return true since this isn't a disallowed call, just not implemented.
+  return true;
+}
+
+void CefFileSystemDelegate::ConfirmSensitiveDirectoryAccess(
+    bool has_write_permission,
+    const std::u16string& app_name,
+    content::WebContents* web_contents,
+    base::OnceClosure on_accept,
+    base::OnceClosure on_cancel) {
+  NOTIMPLEMENTED();
+
+  // Run the cancel callback by default.
+  std::move(on_cancel).Run();
+}
+
+int CefFileSystemDelegate::GetDescriptionIdForAcceptType(
+    const std::string& accept_type) {
+  NOTIMPLEMENTED();
+  return 0;
+}
+
+SavedFilesServiceInterface* CefFileSystemDelegate::GetSavedFilesService(
+    content::BrowserContext* browser_context) {
+  return apps::SavedFilesService::Get(browser_context);
+}
+
+}  // namespace cef
+}  // namespace extensions

libcef/browser/extensions/api/file_system/cef_file_system_delegate.h

@@ -0,0 +1,58 @@
+// 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.
+
+#ifndef CEF_LIBCEF_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_DELEGATE_H_
+#define CEF_LIBCEF_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_DELEGATE_H_
+
+#include <memory>
+
+#include "base/callback.h"
+#include "base/compiler_specific.h"
+#include "base/memory/ref_counted.h"
+#include "extensions/browser/api/execute_code_function.h"
+#include "extensions/browser/api/file_system/file_system_delegate.h"
+#include "extensions/browser/extension_function.h"
+
+namespace content {
+class WebContents;
+}
+
+namespace extensions {
+namespace cef {
+
+class CefFileSystemDelegate : public FileSystemDelegate {
+ public:
+  CefFileSystemDelegate();
+
+  CefFileSystemDelegate(const CefFileSystemDelegate&) = delete;
+  CefFileSystemDelegate& operator=(const CefFileSystemDelegate&) = delete;
+
+  ~CefFileSystemDelegate() override;
+
+  // FileSystemDelegate
+  base::FilePath GetDefaultDirectory() override;
+  base::FilePath GetManagedSaveAsDirectory(
+      content::BrowserContext* browser_context,
+      const Extension& extension) override;
+  bool ShowSelectFileDialog(
+      scoped_refptr<ExtensionFunction> extension_function,
+      ui::SelectFileDialog::Type type,
+      const base::FilePath& default_path,
+      const ui::SelectFileDialog::FileTypeInfo* file_types,
+      FileSystemDelegate::FilesSelectedCallback files_selected_callback,
+      base::OnceClosure file_selection_canceled_callback) override;
+  void ConfirmSensitiveDirectoryAccess(bool has_write_permission,
+                                       const std::u16string& app_name,
+                                       content::WebContents* web_contents,
+                                       base::OnceClosure on_accept,
+                                       base::OnceClosure on_cancel) override;
+  int GetDescriptionIdForAcceptType(const std::string& accept_type) override;
+  SavedFilesServiceInterface* GetSavedFilesService(
+      content::BrowserContext* browser_context) override;
+};
+
+}  // namespace cef
+}  // namespace extensions
+
+#endif  // CEF_LIBCEF_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_DELEGATE_H_