Clang: Do not call DocumentManager::modifiedDocuments() from worker thread

This is unsafe.

Change-Id: I8ac075a7289afa0d84785e37b1325d186a153000
Reviewed-by: Erik Verbruggen <erik.verbruggen@theqtcompany.com>

src/plugins/cpptools/cpptoolsreuse.cpp

@@ -32,6 +32,7 @@
 
 #include "cpptoolsplugin.h"
 
+#include <coreplugin/documentmanager.h>
 #include <coreplugin/editormanager/editormanager.h>
 #include <coreplugin/idocument.h>
 #include <texteditor/convenience.h>
@@ -287,4 +288,13 @@ bool skipFileDueToSizeLimit(const QFileInfo &fileInfo, int limitInMB)
     return false;
 }
 
+Utils::FileNameList modifiedFiles()
+{
+    Utils::FileNameList files;
+    foreach (Core::IDocument *doc, Core::DocumentManager::modifiedDocuments())
+        files.append(doc->filePath());
+    files.removeDuplicates();
+    return files;
+}
+
 } // CppTools