Re-name scheduledCallback -> scheduledHostCallback

Author: acdlite

packages/scheduler/src/Scheduler.js

@@ -534,7 +534,7 @@ if (typeof window !== 'undefined' && window._schedMock) {
     }
   }
 
-  var scheduledCallback = null;
+  var scheduledHostCallback = null;
   var isIdleScheduled = false;
   var timeoutTime = -1;
 
@@ -566,13 +566,18 @@ if (typeof window !== 'undefined' && window._schedMock) {
 
     isIdleScheduled = false;
 
+    var prevScheduledCallback = scheduledHostCallback;
+    var prevTimeoutTime = timeoutTime;
+    scheduledHostCallback = null;
+    timeoutTime = -1;
+
     var currentTime = getCurrentTime();
 
     var didTimeout = false;
     if (frameDeadline - currentTime <= 0) {
       // There's no time left in this idle period. Check if the callback has
       // a timeout and whether it's been exceeded.
-      if (timeoutTime !== -1 && timeoutTime <= currentTime) {
+      if (prevTimeoutTime !== -1 && prevTimeoutTime <= currentTime) {
         // Exceeded the timeout. Invoke the callback even though there's no
         // time left.
         didTimeout = true;
@@ -584,17 +589,16 @@ if (typeof window !== 'undefined' && window._schedMock) {
           requestAnimationFrameWithTimeout(animationTick);
         }
         // Exit without invoking the callback.
+        scheduledHostCallback = prevScheduledCallback;
+        timeoutTime = prevTimeoutTime;
         return;
       }
     }
 
-    timeoutTime = -1;
-    var callback = scheduledCallback;
-    scheduledCallback = null;
-    if (callback !== null) {
+    if (prevScheduledCallback !== null) {
       isPerformingIdleWork = true;
       try {
-        callback(didTimeout);
+        prevScheduledCallback(didTimeout);
       } finally {
         isPerformingIdleWork = false;
       }
@@ -605,7 +609,7 @@ if (typeof window !== 'undefined' && window._schedMock) {
   window.addEventListener('message', idleTick, false);
 
   var animationTick = function(rafTime) {
-    if (scheduledCallback !== null) {
+    if (scheduledHostCallback !== null) {
       // Eagerly schedule the next animation callback at the beginning of the
       // frame. If the scheduler queue is not empty at the end of the frame, it
       // will continue flushing inside that callback. If the queue *is* empty,
@@ -651,7 +655,7 @@ if (typeof window !== 'undefined' && window._schedMock) {
   };
 
   requestHostCallback = function(callback, absoluteTimeout) {
-    scheduledCallback = callback;
+    scheduledHostCallback = callback;
     timeoutTime = absoluteTimeout;
     if (isPerformingIdleWork || absoluteTimeout < 0) {
       // Don't wait for the next frame. Continue working ASAP, in a new event.
@@ -667,7 +671,7 @@ if (typeof window !== 'undefined' && window._schedMock) {
   };
 
   cancelHostCallback = function() {
-    scheduledCallback = null;
+    scheduledHostCallback = null;
     isIdleScheduled = false;
     timeoutTime = -1;
   };