Avoid WTF::Vector::at() and operator[] in core/dom.

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

Index: third_party/WebKit/Source/core/dom/ClientRectList.cpp
diff --git a/third_party/WebKit/Source/core/dom/ClientRectList.cpp b/third_party/WebKit/Source/core/dom/ClientRectList.cpp
index be5ff50c23b990de2e2d6c74bcd71db87f9f87c6..02c2dbf639d86bce53d8837120f45ccb8ad675e4 100644
--- a/third_party/WebKit/Source/core/dom/ClientRectList.cpp
+++ b/third_party/WebKit/Source/core/dom/ClientRectList.cpp
@@ -32,8 +32,8 @@ ClientRectList::ClientRectList() {}
 
 ClientRectList::ClientRectList(const Vector<FloatQuad>& quads) {
   m_list.reserveInitialCapacity(quads.size());
-  for (size_t i = 0; i < quads.size(); ++i)
-    m_list.append(ClientRect::create(quads[i].boundingBox()));
+  for (const auto& quad : quads)
+    m_list.append(ClientRect::create(quad.boundingBox()));
 }
 
 unsigned ClientRectList::length() const {