Add WTF::Vector::emplaceAppend()

third_party/WebKit/Source/wtf/Vector.h

Index: third_party/WebKit/Source/wtf/Vector.h
diff --git a/third_party/WebKit/Source/wtf/Vector.h b/third_party/WebKit/Source/wtf/Vector.h
index 5b50284b29f3c98f244e66884144907583cd4659..5d98d9b8fa829218f512880c3c860137d5418a80 100644
--- a/third_party/WebKit/Source/wtf/Vector.h
+++ b/third_party/WebKit/Source/wtf/Vector.h
@@ -917,6 +917,7 @@ public:
 
     template <typename U> void append(const U*, size_t);
     template <typename U> void append(U&&);
+    template <typename... Args> void emplaceAppend(Args&&...);
     template <typename U> void uncheckedAppend(U&& val);
     template <typename U, size_t otherCapacity, typename V> void appendVector(const Vector<U, otherCapacity, V>&);
 
@@ -1367,6 +1368,23 @@ ALWAYS_INLINE void Vector<T, inlineCapacity, Allocator>::append(U&& val)
     appendSlowCase(std::forward<U>(val));
 }
 
+
+template <typename T, size_t inlineCapacity, typename Allocator>
+template <typename... Args>
+ALWAYS_INLINE void Vector<T, inlineCapacity, Allocator>::emplaceAppend(Args&&... args)
+{
+    static_assert(sizeof...(Args), "grow() must be called instead");
+    static_assert(sizeof...(Args) != 1, "append() must be called instead");
+
+    DCHECK(Allocator::isAllocationAllowed());
+    if (UNLIKELY(size() == capacity()))
+        expandCapacity(size() + 1);
+
+    ANNOTATE_CHANGE_SIZE(begin(), capacity(), m_size, m_size + 1);
+    new (NotNull, end()) T(std::forward<Args>(args)...);
+    ++m_size;
+}
+
 template <typename T, size_t inlineCapacity, typename Allocator>
 template <typename U>
 NEVER_INLINE void Vector<T, inlineCapacity, Allocator>::appendSlowCase(U&& val)