ExtensionDelegate to abstract extension implementation

athena/extensions/extensions_delegate_impl.cc

+// 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.
+
+#include "athena/extensions/public/extensions_delegate.h"
+#include "base/macros.h"
+#include "extensions/common/extension_set.h"
+#include "extensions/shell/browser/shell_extension_system.h"
+
+namespace athena {
+namespace {
+
+ExtensionsDelegate* instance = NULL;
+
+class ShellExtensionsDelegate : public ExtensionsDelegate {
+ public:
+  explicit ShellExtensionsDelegate(content::BrowserContext* context)
+      : context_(context),
+        extension_system_(static_cast<extensions::ShellExtensionSystem*>(
+            extensions::ExtensionSystem::Get(context))) {}
+
+  virtual ~ShellExtensionsDelegate() {}
+
+ private:
+  // ExtensionsDelegate:
+  virtual content::BrowserContext* GetBrowserContext() const OVERRIDE {
+    return context_;
+  }
+  virtual const extensions::ExtensionSet& GetInstalledExtensions() OVERRIDE {
+    shell_extensions_.Clear();
+    if (extension_system_->extension())
+      shell_extensions_.Insert(extension_system_->extension());
+    return shell_extensions_;
+  }
+  virtual void LaunchApp(const std::string& app_id) OVERRIDE {
+    extension_system_->LaunchApp();
+  }
+
+  content::BrowserContext* context_;
+  extensions::ShellExtensionSystem* extension_system_;
+  extensions::ExtensionSet shell_extensions_;
+
+  DISALLOW_COPY_AND_ASSIGN(ShellExtensionsDelegate);
+};
+
+}  // namespace
+
+ExtensionsDelegate::ExtensionsDelegate() {
+  DCHECK(!instance);
+  instance = this;
+}
+
+ExtensionsDelegate::~ExtensionsDelegate() {
+  DCHECK(instance);
+  instance = NULL;
+}
+
+// static
+ExtensionsDelegate* ExtensionsDelegate::Get(content::BrowserContext* context) {
+  DCHECK(instance);
+  DCHECK_EQ(context, instance->GetBrowserContext());
+  return instance;
+}
+
+// static
+void ExtensionsDelegate::CreateExtensionsDelegateForShell(
+    content::BrowserContext* context) {
+  new ShellExtensionsDelegate(context);
+}
+
+// static
+void ExtensionsDelegate::Shutdown() {
+  DCHECK(instance);
+  delete instance;
+}
+
+}  // namespace athena