WTF/std normalization: replace WTF::Vector::first() with ::front()

third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp

Index: third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp
diff --git a/third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp b/third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp
index edbdf687c698704a4a0d502d94230042a587a3f9..4fdb2c418658d49f9d12a998c8b80a9ba4ca2db8 100644
--- a/third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp
+++ b/third_party/WebKit/Source/core/dom/DocumentOrderedMap.cpp
@@ -112,7 +112,7 @@ void DocumentOrderedMap::remove(const AtomicString& key, Element* element) {
   } else {
     if (entry->element == element) {
       DCHECK(entry->orderedList.isEmpty() ||
-             entry->orderedList.first() == element);
+             entry->orderedList.front() == element);
       entry->element =
           entry->orderedList.size() > 1 ? entry->orderedList[1] : nullptr;
     }
@@ -186,7 +186,7 @@ const HeapVector<Member<Element>>& DocumentOrderedMap::getAllElementsById(
       entry->orderedList.uncheckedAppend(element);
     }
     if (!entry->element)
-      entry->element = entry->orderedList.first();
+      entry->element = entry->orderedList.front();
   }
 
   return entry->orderedList;