Editors: Move id() from editor to document.

Change-Id: Ib81076842ab1c16832224790194b001206404d64
Reviewed-by: hjk <hjk121@nokiamail.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/coreplugin/idocument.cpp

@@ -31,6 +31,8 @@
 
 #include "infobar.h"
 
+#include <utils/qtcassert.h>
+
 #include <QFile>
 #include <QFileInfo>
 
@@ -73,6 +75,17 @@ IDocument::~IDocument()
     delete m_infoBar;
 }
 
+void IDocument::setId(Id id)
+{
+    m_id = id;
+}
+
+Id IDocument::id() const
+{
+    QTC_CHECK(m_id.isValid());
+    return m_id;
+}
+
 /*!
     Used for example by EditorManager::openEditorWithContents() to set the contents
     of this document.