Clang: Fix delayed reparse of dirty and visible but not current documents

1. Open document foo.h
2. Create a split and open foo.cpp (#including "foo.h")
3. Edit foo.h (e.g. by introducing a syntax error, so that foo.cpp will
   indicate header errors in the toolbar or as info bar)
=> Actual: foo.cpp will be reparsed immediately.
 Expected: foo.cpp should be reparsed after a delay.

This saves resources (cpu time) and minimizes poping up of the header
info bar while editing header files in splits.

Regression introduced by

    commit 380d756a03
    Clang: Hook up supportive translation unit on first edit

Change-Id: Ib5fd90e49415dfc3aefacab7cd627b0e1937f5fc
Reviewed-by: David Schulz <david.schulz@qt.io>

src/tools/clangbackend/ipcsource/clangcodemodelserver.h

@@ -65,16 +65,22 @@ public: // for tests
     int queueSizeForTestsOnly();
     bool isTimerRunningForTestOnly() const;
     void setUpdateDocumentAnnotationsTimeOutInMsForTestsOnly(int value);
+    void setUpdateVisibleButNotCurrentDocumentsTimeOutInMsForTestsOnly(int value);
     DocumentProcessors &documentProcessors();
 
 private:
-
     void startDocumentAnnotationsTimerIfFileIsNotOpenAsDocument(const Utf8String &filePath);
-    void addJobRequestsForDirtyAndVisibleDocuments();
-    void processJobsForDirtyAndVisibleDocuments();
+
     void processInitialJobsForDocuments(const std::vector<Document> &documents);
     void startInitializingSupportiveTranslationUnits(const std::vector<Document> &documents);
 
+    void processJobsForDirtyAndVisibleDocuments();
+    void processJobsForDirtyCurrentDocument();
+    void processTimerForVisibleButNotCurrentDocuments();
+    void processJobsForDirtyAndVisibleButNotCurrentDocuments();
+
+    void addAndRunUpdateJobs(const std::vector<Document> &documents);
+
     JobRequest createJobRequest(const Document &document,
                                 JobRequest::Type type,
                                 PreferredTranslationUnit preferredTranslationUnit
@@ -88,7 +94,10 @@ private:
     QScopedPointer<DocumentProcessors> documentProcessors_; // Delayed initialization
 
     QTimer updateDocumentAnnotationsTimer;
-    int updateDocumentAnnotationsTimeOutInMs;
+    int updateDocumentAnnotationsTimeOutInMs = 1500;
+
+    QTimer updateVisibleButNotCurrentDocumentsTimer;
+    int updateVisibleButNotCurrentDocumentsTimeOutInMs = 2000;
 };
 
 } // namespace ClangBackEnd