Use C++11 range-based loop for core/clipboard, core/dom and core/testing

Source/core/dom/DocumentMarkerController.cpp

Index: Source/core/dom/DocumentMarkerController.cpp
diff --git a/Source/core/dom/DocumentMarkerController.cpp b/Source/core/dom/DocumentMarkerController.cpp
index 8211471e19280fa2f2830a44b8635520c9a8bfb0..c6a4469aac6ad4ee90a050a96a6e7589ee218cf7 100644
--- a/Source/core/dom/DocumentMarkerController.cpp
+++ b/Source/core/dom/DocumentMarkerController.cpp
@@ -445,9 +445,8 @@ DocumentMarkerVector DocumentMarkerController::markersInRange(Range* range, Docu
     Node* pastLastNode = range->pastLastNode();
     for (Node* node = range->firstNode(); node != pastLastNode; node = NodeTraversal::next(*node)) {
         DocumentMarkerVector markers = markersFor(node);
-        DocumentMarkerVector::const_iterator end = markers.end();
-        for (DocumentMarkerVector::const_iterator it = markers.begin(); it != end; ++it) {
-            DocumentMarker* marker = *it;
+        for (const auto& it : markers) {
+            DocumentMarker* marker = it;
             if (!markerTypes.contains(marker->type()))
                 continue;
             if (node == startContainer && marker->endOffset() <= static_cast<unsigned>(range->startOffset()))
@@ -722,9 +721,8 @@ bool DocumentMarkerController::hasMarkers(Range* range, DocumentMarker::MarkerTy
     Node* pastLastNode = range->pastLastNode();
     for (Node* node = range->firstNode(); node != pastLastNode; node = NodeTraversal::next(*node)) {
         DocumentMarkerVector markers = markersFor(node);
-        DocumentMarkerVector::const_iterator end = markers.end();
-        for (DocumentMarkerVector::const_iterator it = markers.begin(); it != end; ++it) {
-            DocumentMarker* marker = *it;
+        for (const auto& it : markers) {
+            DocumentMarker* marker = it;
             if (!markerTypes.contains(marker->type()))
                 continue;
             if (node == startContainer && marker->endOffset() <= static_cast<unsigned>(range->startOffset()))