Add BlimpClientContext and factory with real and dummy implementation

blimp/client/public/blimp_client_context_delegate.h

+// 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_PUBLIC_BLIMP_CLIENT_CONTEXT_DELEGATE_H_
+#define BLIMP_CLIENT_PUBLIC_BLIMP_CLIENT_CONTEXT_DELEGATE_H_
+
+#include "base/macros.h"
+
+namespace blimp {
+namespace client {
+class BlimpContents;
+
+// BlimpClientContextDelegate is how the BlimpClientContext gets the
+// functionality it needs from its embedder.
+class BlimpClientContextDelegate {
+ public:
+  virtual ~BlimpClientContextDelegate() = default;
+
+  // Attaches any required base::SupportsUserData::Data to the BlimpContents.
+  virtual void AttachBlimpContentsHelpers(BlimpContents* blimp_contents) = 0;
+
+ protected:
+  BlimpClientContextDelegate() = default;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(BlimpClientContextDelegate);
+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_PUBLIC_BLIMP_CLIENT_CONTEXT_DELEGATE_H_