qmljseditor: Improve speed of QML/JS Editor for large files

avoid using extra selections for warnings folding them into the
normal semantic update.

Extra selections impose a relatively large overhead (and need expensive
text cursor operations).
Unlike C++ Qml warnings are continuosly recomputed in the current file
of the editor, but not listed in the issue panel, unless one
explicitly triggers the qml checks.

Using the normal sematic update for warnings avoids QTextCursor
operations, and uses batched applies.

Unfortunately getting the tooltips from the additional formats instead
of using the extra selections requires private API, so Ranges are also
stored separately.

Change-log: [Qml/JS Support] Improved speed of QML/JS Editor for large files with lots of warnings.

Change-Id: I1f996231ef35d7cd77a79af58dbae2098fbbc83e
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Kai Koehne <kai.koehne@digia.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/qmljseditor/qmljseditor.h

@@ -40,6 +40,8 @@
 
 #include <QSharedPointer>
 #include <QModelIndex>
+#include <QTextLayout>
+#include <QVector>
 
 QT_BEGIN_NAMESPACE
 class QComboBox;
@@ -105,6 +107,7 @@ public:
     QmlJSTools::SemanticInfo semanticInfo() const;
     bool isSemanticInfoOutdated() const;
     int editorRevision() const;
+    QVector<QTextLayout::FormatRange> diagnosticRanges() const;
 
     Internal::QmlOutlineModel *outlineModel() const;
     QModelIndex outlineModelIndex();
@@ -113,7 +116,6 @@ public:
 
     TextEditor::IAssistInterface *createAssistInterface(TextEditor::AssistKind assistKind,
                                                         TextEditor::AssistReason reason) const;
-
 public slots:
     virtual void setTabSettings(const TextEditor::TabSettings &ts);
     void reparseDocument();
@@ -192,6 +194,7 @@ private:
     int m_futureSemanticInfoRevision;
 
     QList<TextEditor::QuickFixOperation::Ptr> m_quickFixes;
+    QVector<QTextLayout::FormatRange> m_diagnosticRanges;
 
     QmlJS::IContextPane *m_contextPane;
     int m_oldCursorPosition;