1 files changed, 42 insertions, 0 deletions
diff --git a/chromium/third_party/blink/renderer/core/display_lock/strict_yielding_display_lock_budget.h b/chromium/third_party/blink/renderer/core/display_lock/strict_yielding_display_lock_budget.h
new file mode 100644
index 00000000000..da7512a4520
--- /dev/null
+++ b/chromium/third_party/blink/renderer/core/display_lock/strict_yielding_display_lock_budget.h
@@ -0,0 +1,42 @@
+// Copyright 2018 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.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_DISPLAY_LOCK_STRICT_YIELDING_DISPLAY_LOCK_BUDGET_H_
+#define THIRD_PARTY_BLINK_RENDERER_CORE_DISPLAY_LOCK_STRICT_YIELDING_DISPLAY_LOCK_BUDGET_H_
+
+#include "base/optional.h"
+#include "third_party/blink/renderer/core/core_export.h"
+#include "third_party/blink/renderer/core/display_lock/display_lock_budget.h"
+
+namespace blink {
+
+// This budget yields between lifecycle phases even if that phase is quick. In
+// other words, it will only do one new lifecycle phase at a time, and block the
+// future ones. Any lifecycle phases that have already been allowed by this
+// budget in the past are not blocked.
+class CORE_EXPORT StrictYieldingDisplayLockBudget final
+    : public DisplayLockBudget {
+ public:
+  StrictYieldingDisplayLockBudget(DisplayLockContext*);
+  ~StrictYieldingDisplayLockBudget() override = default;
+
+  bool ShouldPerformPhase(Phase) const override;
+  void DidPerformPhase(Phase) override;
+  void WillStartLifecycleUpdate() override;
+  // Returns true if any of the lifecycles that have been previously blocked by
+  // this budget need updates. Note that this does not check lifecycle phases
+  // that have already completed by this budget even if they are now dirty
+  // again. This is done to prevent starvation (ie, it is possible for the
+  // budget to always schedule more work if something in rAF keeps dirtying
+  // layout, for example).
+  bool NeedsLifecycleUpdates() const override;
+
+ protected:
+  base::Optional<Phase> last_completed_phase_;
+  bool completed_new_phase_this_cycle_;
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_CORE_DISPLAY_LOCK_STRICT_YIELDING_DISPLAY_LOCK_BUDGET_H_