Add BlimpContents[,Observer] and BlimpNavigationController

blimp/client/core/blimp_navigation_controller_delegate.h

Index: blimp/client/core/blimp_navigation_controller_delegate.h
diff --git a/blimp/client/core/blimp_navigation_controller_delegate.h b/blimp/client/core/blimp_navigation_controller_delegate.h
new file mode 100644
index 0000000000000000000000000000000000000000..10647fbd2534eb9a482ee71e57f29e619b0bc53d
--- /dev/null
+++ b/blimp/client/core/blimp_navigation_controller_delegate.h
@@ -0,0 +1,33 @@
+// 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 BLIMP_CLIENT_CORE_BLIMP_NAVIGATION_CONTROLLER_DELEGATE_H_
+#define BLIMP_CLIENT_CORE_BLIMP_NAVIGATION_CONTROLLER_DELEGATE_H_
+
+#include "base/macros.h"
+#include "url/gurl.h"
+
+namespace blimp {
+namespace client {
+
+// Interface for objects embedding a BlimpNavigationControllerImpl to provide
+// the functionality BlimpNavigationControllerImpl needs.
+class BlimpNavigationControllerDelegate {
+ public:
+  virtual ~BlimpNavigationControllerDelegate() = default;
+
+  // Invoked whenever a new URL has been loaded.
+  virtual void NotifyURLLoaded(const GURL& url) = 0;
+
+ protected:
+  BlimpNavigationControllerDelegate() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BlimpNavigationControllerDelegate);
+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_CORE_BLIMP_NAVIGATION_CONTROLLER_DELEGATE_H_