Removing --disable/enable-threaded-compositing cmdline switches.

third_party/WebKit/LayoutTests/virtual/threaded/fast/idleToBlob/OffscreenCanvas-convertToBlob-webgl-worker.html

-<img id="png"/>
-<img id="jpeg-high"/>
-<img id="jpeg-low"/>
-<img id="webp-high"/>
-<img id="webp-low"/>
-<script id="myWorker" type="text/worker">
-self.onmessage = function (e) {
-  var offCanvas = new OffscreenCanvas(50, 50);
-  var gl = offCanvas.getContext('webgl');
-  gl.clearColor(0, 1, 0, 1);
-  gl.clear(gl.COLOR_BUFFER_BIT);
-
-  offCanvas.convertToBlob()
-    .then(function(blob) { 
-      self.postMessage({version: "png", data:blob});
-    });
-
-  offCanvas.convertToBlob({type: "image/jpeg"})
-    .then(function(blob) {
-      self.postMessage({version: "jpeg-high", data:blob});
-    });
-
-  offCanvas.convertToBlob({type: "image/jpeg", quality: 0.2})
-    .then(function(blob) {
-      self.postMessage({version: "jpeg-low", data:blob});
-    });
-
-  offCanvas.convertToBlob({type: "image/webp"})
-    .then(function(blob) { 
-      self.postMessage({version: "webp-high", data:blob});
-    });
-
-  offCanvas.convertToBlob({type: "image/webp", quality: 0.2})
-    .then(function(blob) {
-
-      self.postMessage({version: "webp-low", data:blob});
-    });
-}
-</script>
-<script>
-if (window.testRunner) {
-  testRunner.waitUntilDone();
-}
-
-var pngImage = document.getElementById('png');
-var jpegImageHigh = document.getElementById('jpeg-high');
-var jpegImageLow = document.getElementById('jpeg-low');
-var webpImageHigh = document.getElementById('webp-high');
-var webpImageLow = document.getElementById('webp-low');
-var numTestCount = 5;
-function imageLoaded() {
-  numTestCount--;
-  if (numTestCount == 0 && window.testRunner) {
-    window.testRunner.notifyDone();
-  }
-}
-pngImage.addEventListener('load', imageLoaded);
-jpegImageHigh.addEventListener('load', imageLoaded);
-jpegImageLow.addEventListener('load', imageLoaded);
-webpImageHigh.addEventListener('load', imageLoaded);
-webpImageLow.addEventListener('load', imageLoaded);
-
-var workerBlob = new Blob([document.getElementById('myWorker').textContent]);
-var worker = new Worker(URL.createObjectURL(workerBlob));
-worker.addEventListener("message", function(msg) {
-  var blob = msg.data.data;
-  switch (msg.data.version) {
-    case 'png':
-      pngImage.src = URL.createObjectURL(blob);
-      break;
-    case 'jpeg-high':
-      jpegImageHigh.src = URL.createObjectURL(blob);
-      break;
-    case 'jpeg-low':
-      jpegImageLow.src = URL.createObjectURL(blob);
-      break;
-    case 'webp-high':
-      webpImageHigh.src = URL.createObjectURL(blob);
-      break;
-    case 'webp-low':
-      webpImageLow.src = URL.createObjectURL(blob);
-      break;
-  }
-});
-worker.postMessage("");
-</script>
-