feat: preliminary support for //extensions (#17440)

shell/browser/extensions/atom_extension_loader.h

@@ -0,0 +1,86 @@
+// Copyright 2018 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 SHELL_BROWSER_EXTENSIONS_ATOM_EXTENSION_LOADER_H_
+#define SHELL_BROWSER_EXTENSIONS_ATOM_EXTENSION_LOADER_H_
+
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
+#include "extensions/browser/extension_registrar.h"
+#include "extensions/common/extension_id.h"
+
+namespace base {
+class FilePath;
+}  // namespace base
+
+namespace content {
+class BrowserContext;
+}  // namespace content
+
+namespace extensions {
+
+class Extension;
+
+// Handles extension loading and reloading using ExtensionRegistrar.
+class AtomExtensionLoader : public ExtensionRegistrar::Delegate {
+ public:
+  explicit AtomExtensionLoader(content::BrowserContext* browser_context);
+  ~AtomExtensionLoader() override;
+
+  // Loads an unpacked extension from a directory synchronously. Returns the
+  // extension on success, or nullptr otherwise.
+  const Extension* LoadExtension(const base::FilePath& extension_dir);
+
+  // Starts reloading the extension. A keep-alive is maintained until the
+  // reload succeeds/fails. If the extension is an app, it will be launched upon
+  // reloading.
+  // This may invalidate references to the old Extension object, so it takes the
+  // ID by value.
+  void ReloadExtension(ExtensionId extension_id);
+
+ private:
+  // If the extension loaded successfully, enables it. If it's an app, launches
+  // it. If the load failed, updates ShellKeepAliveRequester.
+  void FinishExtensionReload(const ExtensionId old_extension_id,
+                             scoped_refptr<const Extension> extension);
+
+  // ExtensionRegistrar::Delegate:
+  void PreAddExtension(const Extension* extension,
+                       const Extension* old_extension) override;
+  void PostActivateExtension(scoped_refptr<const Extension> extension) override;
+  void PostDeactivateExtension(
+      scoped_refptr<const Extension> extension) override;
+  void LoadExtensionForReload(
+      const ExtensionId& extension_id,
+      const base::FilePath& path,
+      ExtensionRegistrar::LoadErrorBehavior load_error_behavior) override;
+  bool CanEnableExtension(const Extension* extension) override;
+  bool CanDisableExtension(const Extension* extension) override;
+  bool ShouldBlockExtension(const Extension* extension) override;
+
+  content::BrowserContext* browser_context_;  // Not owned.
+
+  // Registers and unregisters extensions.
+  ExtensionRegistrar extension_registrar_;
+
+  // Holds keep-alives for relaunching apps.
+  //   ShellKeepAliveRequester keep_alive_requester_;
+
+  // Indicates that we posted the (asynchronous) task to start reloading.
+  // Used by ReloadExtension() to check whether ExtensionRegistrar calls
+  // LoadExtensionForReload().
+  bool did_schedule_reload_ = false;
+
+  base::WeakPtrFactory<AtomExtensionLoader> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(AtomExtensionLoader);
+};
+
+}  // namespace extensions
+
+#endif  // SHELL_BROWSER_EXTENSIONS_ATOM_EXTENSION_LOADER_H_