Add layout states to DocumentLifecycle state machine

Source/core/frame/DeprecatedScheduleStyleRecalcDuringLayout.cpp

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/frame/DeprecatedScheduleStyleRecalcDuringLayout.h"
+
+#include "wtf/Assertions.h"
+
+namespace WebCore {
+
+DeprecatedScheduleStyleRecalcDuringLayout::DeprecatedScheduleStyleRecalcDuringLayout(DocumentLifecycle& lifecycle)
+    : m_lifecycle(lifecycle)
+    , m_deprecatedTransition(DocumentLifecycle::InPerformLayout, DocumentLifecycle::StyleRecalcPending)
+    , m_wasInPerformLayout(lifecycle.state() == DocumentLifecycle::InPerformLayout)
+{
+}
+
+DeprecatedScheduleStyleRecalcDuringLayout::~DeprecatedScheduleStyleRecalcDuringLayout()
+{
+    // This block of code is intended to restore the state machine to the
+    // proper state. The style recalc will still have been schedule, however.
+    if (m_wasInPerformLayout && m_lifecycle.state() != DocumentLifecycle::InPerformLayout) {
+        ASSERT(m_lifecycle.state() == DocumentLifecycle::StyleRecalcPending);
+        m_lifecycle.advanceTo(DocumentLifecycle::InPerformLayout);
+    }
+}
+
+}