Add missing headers

Author: Naveen Seth Hanig

clang/include/clang/DependencyScanning/DependencyScanningUtils.h

@@ -12,6 +12,10 @@
 #include "clang/DependencyScanning/DependencyScannerImpl.h"
 #include "clang/DependencyScanning/DependencyScanningWorker.h"
 #include "clang/DependencyScanning/ModuleDepCollector.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/MapVector.h"
+#include <string>
+#include <vector>
 
 namespace clang {
 namespace dependencies {