Wires up shelf to panel and dock layoutmanagers

mash/wm/shelf_layout_manager_delegate.h

Index: mash/wm/shelf_layout_manager_delegate.h
diff --git a/mash/wm/shelf_layout_manager_delegate.h b/mash/wm/shelf_layout_manager_delegate.h
new file mode 100644
index 0000000000000000000000000000000000000000..53372c0a4ab26837bd7dbab0cdd5dab43ef63ba2
--- /dev/null
+++ b/mash/wm/shelf_layout_manager_delegate.h
@@ -0,0 +1,24 @@
+// Copyright 2016 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 MASH_WM_SHELF_LAYOUT_MANAGER_DELEGATE_H_
+#define MASH_WM_SHELF_LAYOUT_MANAGER_DELEGATE_H_
+
+namespace mash {
+namespace wm {
+
+class ShelfLayoutManagerDelegate {
+ public:
+  // Called when the window associated with the shelf is available. That is,
+  // ShelfLayoutManager::GetShelfWindow() returns non-null.
+  virtual void OnShelfWindowAvailable() = 0;
+
+ protected:
+  virtual ~ShelfLayoutManagerDelegate() {}
+};
+
+}  // namespace wm
+}  // namespace mash
+
+#endif  // MASH_WM_SHELF_LAYOUT_MANAGER_DELEGATE_H_