CppTools: Turn some classes into pure value types

ProjectInfo, ProjectPart and ProjectUpdateInfo used to carry pointers
to Project and/or Toolchain, even though they were used in contexts
where these pointers were either unsafe to access or not guaranteed to
be valid anymore, which made their use difficult and error-prone.
We turn these classes into pure value types by copying in all relevant
information before the first async operation takes place.

Fixes: QTCREATORBUG-25678
Change-Id: I1914b0dbda6c7dfba6c95e5e92f2d69977755590
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/clangcodemodel/clangmodelmanagersupport.h

@@ -29,6 +29,7 @@
 #include "clanguiheaderondiskmanager.h"
 
 #include <cpptools/cppmodelmanagersupport.h>
+#include <cpptools/projectinfo.h>
 
 #include <utils/futuresynchronizer.h>
 #include <utils/id.h>
@@ -129,7 +130,7 @@ private:
     void connectToWidgetsMarkContextMenuRequested(QWidget *editorWidget);
 
     void updateLanguageClient(ProjectExplorer::Project *project,
-                              const CppTools::ProjectInfo &projectInfo);
+                              const CppTools::ProjectInfo::Ptr &projectInfo);
     ClangdClient *createClient(ProjectExplorer::Project *project, const Utils::FilePath &jsonDbDir);
     void claimNonProjectSources(ClangdClient *fallbackClient);