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

third_party/WebKit/Source/platform/graphics/paint/PaintChunker.cpp

Index: third_party/WebKit/Source/platform/graphics/paint/PaintChunker.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/paint/PaintChunker.cpp b/third_party/WebKit/Source/platform/graphics/paint/PaintChunker.cpp
index 1a64e54946f81f11bef07606ec7f56855b48b2ab..c4f087aa853f5d02c1edbc12f71591d18fe7d2d3 100644
--- a/third_party/WebKit/Source/platform/graphics/paint/PaintChunker.cpp
+++ b/third_party/WebKit/Source/platform/graphics/paint/PaintChunker.cpp
@@ -72,10 +72,10 @@ bool PaintChunker::incrementDisplayItemIndex(const DisplayItem& item) {
     return true;
   }
 
-  auto& lastChunk = m_chunks.last();
+  auto& lastChunk = m_chunks.back();
   bool canContinueChunk = m_currentProperties == lastChunk.properties &&
                           behavior != RequiresSeparateChunk &&
-                          m_chunkBehavior.last() != RequiresSeparateChunk;
+                          m_chunkBehavior.back() != RequiresSeparateChunk;
   if (canContinueChunk) {
     lastChunk.endIndex++;
     return false;
@@ -92,7 +92,7 @@ bool PaintChunker::decrementDisplayItemIndex() {
   DCHECK(RuntimeEnabledFeatures::slimmingPaintV2Enabled());
   DCHECK(!m_chunks.isEmpty());
 
-  auto& lastChunk = m_chunks.last();
+  auto& lastChunk = m_chunks.back();
   if ((lastChunk.endIndex - lastChunk.beginIndex) > 1) {
     lastChunk.endIndex--;
     return false;