[examples] custom-layer examples errors out due to tf.browser.fromPixels()

[caisq]

To get help from the community, we encourage using Stack Overflow and the tensorflow.js tag.

TensorFlow.js version

1.2.6, 1.2.7, 1.2.8 all show this issue.
Other versions not tested.

Browser version

Chrome Linux Version 76.0.3809.100 (Official Build) (64-bit)
Firefox Linux 60.8.0esr (64-bit)

Describe the problem or feature request

Launch the custom-layer example from tfjs-examples. Observe the error message:

Uncaught Error: The DOM is not ready yet. Please call tf.browser.fromPixels() once the DOM is ready. One way to do that is to add an event listener for DOMContentLoaded on the document object
at t.fromPixels (backend_webgl.ts:316)
at t.fromPixels (engine.ts:870)
at fromPixels_ (browser.ts:55)
at Object.fromPixels (operation.ts:45)
at customLayerDemo (index.js:25)
at Object.parcelRequire.index.js.@tensorflow/tfjs (index.js:56)
at newRequire (custom-layer.e31bb0bc.js:49)
at custom-layer.e31bb0bc.js:81
at custom-layer.e31bb0bc.js:107

Adding document.addEventListener('DOMContentLoaded', ...) doesn't seem to help

Code to reproduce the bug / link to feature request

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GitHub issues for this repository are tracked in the tfjs union repository.

Please file your issue there, following the guidance in that issue template.

[nsthorat]

What about adding addEventListener('ready')? I think this PR will fix the error: #1852

[bileschi]

Can reproduce.

[dsmilkov]

This was fixed in #1947 by @nsthorat