requestIdleCallback: Yield for high priority work

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

 // Copyright 2015 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 "core/dom/IdleDeadline.h"
 
 #include "core/timing/PerformanceBase.h"
+#include "public/platform/Platform.h"
+#include "public/platform/WebScheduler.h"
 #include "wtf/CurrentTime.h"
 
 namespace blink {
 
 IdleDeadline::IdleDeadline(double deadlineSeconds, CallbackType callbackType)
     : m_deadlineSeconds(deadlineSeconds), m_callbackType(callbackType) {}
 
 double IdleDeadline::timeRemaining() const {
   double timeRemaining = m_deadlineSeconds - monotonicallyIncreasingTime();
-  if (timeRemaining < 0)
+  if (timeRemaining < 0) {
     timeRemaining = 0;

[esprehn, 2016/11/21 20:32:27]

Early return in blink.

if (timeRemaining < 0)
  return 0;

if (....)
  return 0;

return 1000.0 * PerformanceBase::clampTimeResolution(timeRemaining);

+  } else if (Platform::current()
+                 ->currentThread()
+                 ->scheduler()
+                 ->shouldYieldForHighPriorityWork()) {
+    timeRemaining = 0;
+  }
 
   return 1000.0 * PerformanceBase::clampTimeResolution(timeRemaining);
 }
 
 }  // namespace blink