Migrate TabControlFeature from 0.5 to 0.6

blimp/client/core/contents/blimp_contents_manager.h

Index: blimp/client/core/contents/blimp_contents_manager.h
diff --git a/blimp/client/core/contents/blimp_contents_manager.h b/blimp/client/core/contents/blimp_contents_manager.h
new file mode 100644
index 0000000000000000000000000000000000000000..ea70960ffbccffc7eb48072e9d5784c2de681fab
--- /dev/null
+++ b/blimp/client/core/contents/blimp_contents_manager.h
@@ -0,0 +1,51 @@
+// 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_CONTENTS_BLIMP_CONTENTS_MANAGER_H_
+#define BLIMP_CLIENT_CORE_CONTENTS_BLIMP_CONTENTS_MANAGER_H_
+
+#include "blimp/client/core/contents/blimp_contents_impl.h"
+
+namespace blimp {
+namespace client {
+
+// BlimpContentsManager does the real work of creating BlimpContentsImpl, and
+// then passes the ownership to the caller. It also owns the observers to
+// monitor the life time of the contents it creates.
+class BlimpContentsManager {
+ public:
+  BlimpContentsManager();
+  ~BlimpContentsManager();
+
+  std::unique_ptr<BlimpContentsImpl> CreateBlimpContents();
+
+  // The caller can query the contents through its id.
+  BlimpContentsImpl* GetBlimpContents(int id);
+
+ private:
+  class BlimpContentsDeletionObserver;
+  friend class BlimpContentsDeletionObserver;
+
+  // When creating the BlimpContentsImpl, an id is created for the content.
+  int CreateBlimpContentsId();
+
+  // When a BlimpContentsImpl is destroyed, its observer is able to retrieve the
+  // id, and use this to destroy the observer entry from the observer_map_.
+  void EraseObserverFromMap(int id);
+  base::WeakPtr<BlimpContentsManager> GetWeakPtr();
+
+  // BlimpContentsManager owns the BlimpContentsDeletionObserver for the
+  // contents it creates, with the content id being the key to help manage the
+  // lifetime of the observers.
+  std::map<int, std::unique_ptr<BlimpContentsDeletionObserver>> observer_map_;
+
+  base::WeakPtrFactory<BlimpContentsManager> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(BlimpContentsManager);
+};
+
+}  // namespace client
+}  // namespace blimp
+
+#endif  // BLIMP_CLIENT_CORE_CONTENTS_BLIMP_CONTENTS_MANAGER_H_