app-shell: Introduce a ShellRendererMainDelegate.

apps/shell/renderer/shell_renderer_main_delegate.h

+// 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.
+
+#ifndef APPS_SHELL_RENDERER_SHELL_RENDERER_MAIN_DELEGATE_H_
+#define APPS_SHELL_RENDERER_SHELL_RENDERER_MAIN_DELEGATE_H_
+
+namespace content {
+class RenderThread;
+class RenderView;
+}
+
+namespace apps {
+
+class ShellRendererMainDelegate {
+ public:
+  virtual ~ShellRendererMainDelegate() {}
+
+  // Called when |thread| is started, after the extensions subsystem has been
+  // initialized for |thread|.
+  virtual void OnThreadStarted(content::RenderThread* thread) = 0;
+
+  // Called for each RenderView created in the renderer process, after the
+  // extension related code has been initialized for the view.
+  virtual void OnViewCreated(content::RenderView* view) = 0;
+};
+
+}  // namespace apps
+
+#endif  // APPS_SHELL_RENDERER_SHELL_RENDERER_MAIN_DELEGATE_H_