CppTools: Add revisions to AbstractEditorSupport

So far revisions for AbstractEditorSupport were not needed because until
recently we only had a single snapshot ("global snapshot"). Now, since
editor snapshots are introduced, we need to make sure to update the
corresponding documents in these snapshots, too. To do this efficiently,
a revision is introduced for AbstractEditorSupport.

Task-number: QTCREATORBUG-10894

Change-Id: Ibad1dbbafb7c721d1328959c1e903345fe465326
Reviewed-by: Christian Stenger <christian.stenger@digia.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>

src/plugins/cpptools/abstracteditorsupport.cpp

@@ -38,7 +38,7 @@
 namespace CppTools {
 
 AbstractEditorSupport::AbstractEditorSupport(CppModelManagerInterface *modelmanager) :
-    m_modelmanager(modelmanager)
+    m_modelmanager(modelmanager), m_revision(0)
 {
 }
 
@@ -48,6 +48,7 @@ AbstractEditorSupport::~AbstractEditorSupport()
 
 void AbstractEditorSupport::updateDocument()
 {
+    ++m_revision;
     m_modelmanager->updateSourceFiles(QStringList(fileName()));
 }