1 files changed, 49 insertions, 0 deletions
diff --git a/layout/base/nsAutoLayoutPhase.h b/layout/base/nsAutoLayoutPhase.h
new file mode 100644
index 0000000000..cba7a644f9
--- /dev/null
+++ b/layout/base/nsAutoLayoutPhase.h
@@ -0,0 +1,49 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef nsAutoLayoutPhase_h
+#define nsAutoLayoutPhase_h
+
+#ifdef DEBUG
+
+#  include <stdint.h>
+
+enum class nsLayoutPhase : uint8_t;
+class nsPresContext;
+
+struct nsAutoLayoutPhase {
+  nsAutoLayoutPhase(nsPresContext* aPresContext, nsLayoutPhase aPhase);
+  ~nsAutoLayoutPhase();
+
+  void Enter();
+  void Exit();
+
+ private:
+  nsPresContext* mPresContext;
+  nsLayoutPhase mPhase;
+  uint32_t mCount;
+};
+
+#  define AUTO_LAYOUT_PHASE_ENTRY_POINT(pc_, phase_) \
+    nsAutoLayoutPhase autoLayoutPhase((pc_), (nsLayoutPhase::phase_))
+#  define LAYOUT_PHASE_TEMP_EXIT() \
+    PR_BEGIN_MACRO                 \
+    autoLayoutPhase.Exit();        \
+    PR_END_MACRO
+#  define LAYOUT_PHASE_TEMP_REENTER() \
+    PR_BEGIN_MACRO                    \
+    autoLayoutPhase.Enter();          \
+    PR_END_MACRO
+
+#else  // DEBUG
+
+#  define AUTO_LAYOUT_PHASE_ENTRY_POINT(pc_, phase_) PR_BEGIN_MACRO PR_END_MACRO
+#  define LAYOUT_PHASE_TEMP_EXIT() PR_BEGIN_MACRO PR_END_MACRO
+#  define LAYOUT_PHASE_TEMP_REENTER() PR_BEGIN_MACRO PR_END_MACRO
+
+#endif  // DEBUG
+
+#endif  // nsAutoLayoutPhase_h