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 {
+  if (Platform::current()
+          ->currentThread()
+          ->scheduler()
+          ->shouldYieldForHighPriorityWork()) {
+    return 0;
+  }

[rmcilroy, 2016/11/18 09:13:51]

nit - how about just setting timeRemaining to zero, and only doing the check I'd
timeRemaining != 0?

[Sami, 2016/11/21 11:28:02]

Good idea, done.

+
   double timeRemaining = m_deadlineSeconds - monotonicallyIncreasingTime();
   if (timeRemaining < 0)
     timeRemaining = 0;
 
   return 1000.0 * PerformanceBase::clampTimeResolution(timeRemaining);
 }
 
 }  // namespace blink