Introduced a token cache for the C++ editor.

This should speed things up a bit, because before, the line was tokenized at
least 3 times.

src/plugins/cpptools/cpptoolseditorsupport.h

@@ -36,6 +36,7 @@
 #include <QSharedPointer>
 #include <QTextCursor>
 #include <cplusplus/CppDocument.h>
+#include <cplusplus/TokenCache.h>
 
 QT_BEGIN_NAMESPACE
 class QTimer;
@@ -72,6 +73,8 @@ public:
     QString contents();
     unsigned editorRevision() const;
 
+    CPlusPlus::TokenCache *tokenCache();
+
 Q_SIGNALS:
     void contentsChanged();
 
@@ -89,6 +92,7 @@ private:
     QFuture<void> _documentParser;
     QString _cachedContents;
     unsigned _revision;
+    CPlusPlus::TokenCache _tokenCache;
 };
 
 } // namespace Internal