Calls to window.requestLayoutFrame() sometimes shows javascript console message 'Uncaught TypeError: Cannot read property 'length' of null'

[DartBot]

This issue was originally filed by prujoh...@gmail.com

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What steps will reproduce the problem?
I think it has to do when making multiple calls to window.requestLayoutFrame under certain circumstances. I must confess I can reproduce this in my own code, but have been unable to isolate it to a simple example.

What is the expected output? What do you see instead?
Everything renders fine on the browser, but the javascript console displays this message:
Uncaught TypeError: Cannot read property 'length' of null
_completeMeasurementFutures
_maybeScheduleMeasurementFrame.$globals._firstMeasurementRequest
wrapped

Digging in to the javascript itself I see that it's happening here when $globals._pendingRequests returns null in this function:

function _completeMeasurementFutures() {
  if ($eq($globals._nextMeasurementFrameScheduled, false)) {
    return;
  }
  $globals._nextMeasurementFrameScheduled = false;
  var $list = $globals._pendingRequests;
  for (var $i = 0;$i < $list.length; $i++) {
//LUCA_UI_Demo.dart.app.js:3983 Uncaught TypeError: Cannot read //property 'length' of null
    var request = $list.$index($i);
    try {
      request.value = request.computeValue();
    } catch (e) {
      e = _toDartException(e);
      request.value = e;
      request.exception = true;
    }
  }

What version of the product are you using? On what operating system?
frog, Ubuntu

Please provide any additional information below.

[DartBot]

This comment was originally written by drfibonacci@google.com

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Added Area-Frog, Triaged labels.

[dgrove]

Set owner to @jacob314.
Removed Area-Frog label.
Added Area-UI label.

[dgrove]

Without repro info, presuming that this has been fixed over the past few months.

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Added AssumedStale label.