Initial touch-action main thread implementation

Source/web/tests/data/touch-action-tests.js

+// For manual testing, disable compositor hit testing
+document.addEventListener('touchstart', function() {});
+
+/*
+ * Visualization of hit test locations for manual testing.
+ * Note that JS is not run as part of the unit test.
+ */
+function addMarker(x, y)
+{
+    const kMarkerSize = 6;
+    var marker = document.createElement('div');
+    marker.className = 'marker';
+    marker.style.top = (y - kMarkerSize/2) + "px";
+    marker.style.left = (x - kMarkerSize/2) + "px";
+    document.body.appendChild(marker);
+}
+
+window.addEventListener('load', function() {
+  var tests = document.querySelectorAll('[expected-action]');
+  for( var i = 0; i < tests.length; i++) {
+    var r = tests[i].getClientRects()[0];
+    addMarker(r.left, r.top);
+    addMarker(r.right - 1, r.bottom - 1);
+    addMarker(r.left + r.width / 2, r.top + r.height / 2);
+  }
+});