Add BlimpContents[,Observer] and BlimpNavigationController

blimp/client/core/public/blimp_contents.h

Index: blimp/client/core/public/blimp_contents.h
diff --git a/blimp/client/core/public/blimp_contents.h b/blimp/client/core/public/blimp_contents.h
new file mode 100644
index 0000000000000000000000000000000000000000..5da71d27d3d5d4aa9c59e33f536842257da80b41
--- /dev/null
+++ b/blimp/client/core/public/blimp_contents.h
@@ -0,0 +1,43 @@
+// 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_PUBLIC_BLIMP_CONTENTS_H_
+#define BLIMP_CLIENT_CORE_PUBLIC_BLIMP_CONTENTS_H_
+
+#include "base/macros.h"
+#include "url/gurl.h"
+
+namespace blimp {
+namespace client {
+
+class BlimpContentsObserver;
+class BlimpNavigationController;
+
+// BlimpContents is the core class in //blimp/client/core. It renders web pages
+// from an engine in a rectangular area.
+// It enables callers to control the blimp engine through the use of the
+// navigation controller.
+class BlimpContents {
+ public:
+  virtual ~BlimpContents() = default;
+
+  // Retrives the navigation controller that controls all navigation related
+  // to this BlimpContents.
+  virtual BlimpNavigationController& GetNavigationController() = 0;
+
+  // Enables adding and removing observers to this BlimpContents.
+  virtual void AddObserver(BlimpContentsObserver* observer) = 0;
+  virtual void RemoveObserver(BlimpContentsObserver* observer) = 0;
+
+ protected:
+  BlimpContents() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BlimpContents);
+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_CORE_PUBLIC_BLIMP_CONTENTS_H_