Designer/CppTools: Fix flaky test_gotoslot_withoutProject

The document was not always updated in time.

Change-Id: Iac89985d39a8784e3cbf63dfd42b1c5150775068
Reviewed-by: Christian Stenger <christian.stenger@digia.com>

src/plugins/cpptools/cppmodelmanager.cpp

@@ -461,7 +461,7 @@ CppEditorSupport *CppModelManager::cppEditorSupport(TextEditor::BaseTextEditor *
     QMutexLocker locker(&m_cppEditorSupportsMutex);
 
     CppEditorSupport *editorSupport = m_cppEditorSupports.value(textEditor, 0);
-    if (!editorSupport) {
+    if (!editorSupport && isCppEditor(textEditor)) {
         editorSupport = new CppEditorSupport(this, textEditor);
         m_cppEditorSupports.insert(textEditor, editorSupport);
     }

src/plugins/cpptools/cpptoolseditorsupport.cpp

@@ -308,6 +308,11 @@ void CppEditorSupport::updateDocumentNow()
     }
 }
 
+bool CppEditorSupport::isUpdatingDocument()
+{
+    return m_updateDocumentTimer->isActive() || m_documentParser.isRunning();
+}
+
 void CppEditorSupport::onDocumentUpdated(Document::Ptr doc)
 {
     if (doc.isNull())

src/plugins/cpptools/cpptoolseditorsupport.h

@@ -125,6 +125,9 @@ public:
 
     QSharedPointer<SnapshotUpdater> snapshotUpdater();
 
+    /// Checks whether the document is (re)parsed or about to be (re)parsed.
+    bool isUpdatingDocument();
+
 signals:
     void documentUpdated();
     void diagnosticsChanged();