AutoTest: Avoid full rescans if not necessary

The file system watcher triggers way too often as it
acts not only for removal or addition of files, but
for any change like mtime or similar.
Doing always a full rescan is painful, so limit this
as much as possible to the files that have changed.

Task-number: QTCREATORBUG-18315
Change-Id: Iba4705ff58c34e998d8cf1b40761758c6fd65680
Reviewed-by: David Schulz <david.schulz@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/autotest/quick/quicktestparser.h

@@ -56,10 +56,13 @@ signals:
 private:
     bool handleQtQuickTest(QFutureInterface<TestParseResultPtr> futureInterface,
                            CPlusPlus::Document::Ptr document, const Core::Id &id) const;
+    void handleDirectoryChanged(const QString &directory);
+    void doUpdateWatchPaths(const QStringList &directories);
     QList<QmlJS::Document::Ptr> scanDirectoryForQuickTestQmlFiles(const QString &srcDir) const;
     QmlJS::Snapshot m_qmlSnapshot;
     QHash<QString, QString> m_proFilesForQmlFiles;
     QFileSystemWatcher m_directoryWatcher;
+    QMap<QString, QMap<QString, QDateTime> > m_watchedFiles;
 };
 
 } // namespace Internal