Clang: Add source dependency saving to the symbol storage

The source dependencies are simply a table which connects the include file
with the included file.

Change-Id: I5454e81a2b5b98f05c7ff3f6740a6d45e01772c3
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/tools/clangrefactoringbackend/source/sourcedependency.h

@@ -0,0 +1,56 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#pragma once
+
+#include <filepathid.h>
+
+#include <vector>
+
+namespace ClangBackEnd {
+
+class SourceDependency
+{
+public:
+    SourceDependency(FilePathId filePathId,
+                    FilePathId dependencyFilePathId)
+        : filePathId(filePathId),
+          dependencyFilePathId(dependencyFilePathId)
+    {}
+
+    friend
+    bool operator==(SourceDependency first, SourceDependency second)
+    {
+        return first.filePathId == second.filePathId
+            && first.dependencyFilePathId == second.dependencyFilePathId;
+    }
+
+public:
+    FilePathId filePathId;
+    FilePathId dependencyFilePathId;
+};
+
+using SourceDependencies = std::vector<SourceDependency>;
+}