WTF/std normalization: replace WTF::Vector::last with ::back

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

Index: third_party/WebKit/Source/core/dom/Fullscreen.cpp
diff --git a/third_party/WebKit/Source/core/dom/Fullscreen.cpp b/third_party/WebKit/Source/core/dom/Fullscreen.cpp
index 9c124101037fbd3ff7c15d643bf029d91705330e..380a2438ffe881ba7375f8c08e19fd17fdf73dae 100644
--- a/third_party/WebKit/Source/core/dom/Fullscreen.cpp
+++ b/third_party/WebKit/Source/core/dom/Fullscreen.cpp
@@ -470,7 +470,7 @@ void Fullscreen::exitFullscreen(Document& document) {
   for (auto& descendant : descendants) {
     DCHECK(descendant);
     RequestType requestType =
-        from(*descendant).m_fullscreenElementStack.last().second;
+        from(*descendant).m_fullscreenElementStack.back().second;
     from(*descendant).clearFullscreenElementStack();
     from(document).enqueueChangeEvent(*descendant, requestType);
   }
@@ -479,7 +479,7 @@ void Fullscreen::exitFullscreen(Document& document) {
   Element* newTop = nullptr;
   for (Document* currentDoc = &document; currentDoc;) {
     RequestType requestType =
-        from(*currentDoc).m_fullscreenElementStack.last().second;
+        from(*currentDoc).m_fullscreenElementStack.back().second;
 
     // 1. Pop the top element of doc's fullscreen element stack.
     from(*currentDoc).popFullscreenElementStack();