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/clangtools/clangselectablefilesdialog.cpp

@@ -264,14 +264,14 @@ private:
     }
 };
 
-SelectableFilesDialog::SelectableFilesDialog(const ProjectInfo &projectInfo,
+SelectableFilesDialog::SelectableFilesDialog(Project *project,
                                              const FileInfoProviders &fileInfoProviders,
                                              int initialProviderIndex)
     : QDialog(nullptr)
     , m_ui(new Ui::SelectableFilesDialog)
     , m_filesModel(new SelectableFilesModel)
     , m_fileInfoProviders(fileInfoProviders)
-    , m_project(projectInfo.project())
+    , m_project(project)
     , m_analyzeButton(new QPushButton(tr("Analyze"), this))
 {
     m_ui->setupUi(this);