ClangRefactoring: Process tasks after a task has been finished

It could be that processTasks is executed before the future is finished
but in that case there are other tasks which will be called later.

Change-Id: I9b1bfb6fdd642f23842b9c70d60d5b1552193b99
Reviewed-by: Ivan Donchevskii <ivan.donchevskii@qt.io>

src/tools/clangrefactoringbackend/source/symbolindexertaskqueue.h

@@ -25,6 +25,8 @@
 
 #pragma once
 
+#include "symbolindexertaskqueueinterface.h"
+
 #include <filepathid.h>
 
 #include <utils/smallstringvector.h>
@@ -92,6 +94,8 @@ public:
     std::vector<std::size_t> projectPartNumberIds(const Utils::SmallStringVector &projectPartIds)
     /* [[ensures result: std::is_sorted(result)]] */;
 
+    void processTasks() ;
+
 private:
     std::vector<Utils::SmallString> m_projectPartIds;
     std::vector<SymbolIndexerTask> m_tasks;