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/cppmodelmanagerinterface.h

@@ -40,16 +40,25 @@
 
 namespace CPlusPlus {
     class LookupContext;
+    class TokenCache;
 }
 
 namespace ProjectExplorer {
     class Project;
 }
 
+namespace TextEditor {
+    class ITextEditor;
+}
+
 namespace CppTools {
 
 class AbstractEditorSupport;
 
+namespace Internal {
+class CppEditorSupport;
+}
+
 class CPPTOOLS_EXPORT CppModelManagerInterface : public QObject
 {
     Q_OBJECT
@@ -130,6 +139,8 @@ public:
 
     virtual void findMacroUsages(const CPlusPlus::Macro &macro) = 0;
 
+    virtual CPlusPlus::TokenCache *tokenCache(TextEditor::ITextEditor *editor) const = 0;
+
 Q_SIGNALS:
     void documentUpdated(CPlusPlus::Document::Ptr doc);