Clang: Auto reparse if diagnostic config changes

On diagnostic config change, affected documents are closed behind the
scenes. Visible ones are parsed immediately, invisible ones are tagged
for parse once they become visible.

Task-number: QTCREATORBUG-16263
Change-Id: Id4dcc69f1a4bfccc597e798d6821f8718f86e352
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangeditordocumentprocessor.h

@@ -28,6 +28,7 @@
 #include "clangdiagnosticmanager.h"
 #include "clangeditordocumentparser.h"
 
+#include <coreplugin/id.h>
 #include <cpptools/builtineditordocumentprocessor.h>
 #include <cpptools/semantichighlighter.h>
 
@@ -67,6 +68,8 @@ public:
     CppTools::ProjectPart::Ptr projectPart() const;
     void clearProjectPart();
 
+    Core::Id diagnosticConfigId() const;
+
     void updateCodeWarnings(const QVector<ClangBackEnd::DiagnosticContainer> &diagnostics,
                             const ClangBackEnd::DiagnosticContainer &firstHeaderErrorDiagnostic,
                             uint documentRevision);
@@ -120,6 +123,7 @@ private:
     BackendCommunicator &m_communicator;
     QSharedPointer<ClangEditorDocumentParser> m_parser;
     CppTools::ProjectPart::Ptr m_projectPart;
+    Core::Id m_diagnosticConfigId;
     bool m_isProjectFile = false;
     QFutureWatcher<void> m_parserWatcher;
     QTimer m_updateTranslationUnitTimer;