Prevent further tracking by blocking additional methods

[pes10k]

• Did you search for similar issues before submitting this one?
  Yap

• Describe the issue you encountered:
  There are a large number of methods that are overwhelmingly (>95%) used for tracking on the web, but which are currently not blocked out with shields up. Many of these would make good candidates for blocking

• Platform (Win7, 8, 10? macOS? Linux distro?):
  all

• Brave Version (revision SHA):
  00cc603

• Steps to reproduce:

  1. Try calling a tracking related method, like SVGTextContentElement.prototype.getComputedTextLength()

• Actual result:
  The method works as the standard defines

• Expected result:
  Access to it to be blocked in shields up mode

• Will the steps above reproduce in a fresh profile? If not what other info can be added?
  Yep

• Is this an issue in the currently released version?
  Yep

• Can this issue be consistently reproduced?
  Yep

The below is a list of methods that we found to have a 95% or more reduction in use when installing Ghostery, and which are used on >= 100 sites in the Alexa 10k at the time of measurement (~1.5 years ago…). Some methods that are heavily related to tracking are

• SVGTextContentElement.prototype.getComputedTextLength
• CanvasRenderingContext2D.prototype.quadraticCurveTo
• MessagePort.prototype.start
• Document.prototype.elementFromPoint

There are many other compelling "options" on the list

feature_name	num_sites_using	pct_reduction_when_blocking
CanvasRenderingContext2D.prototype.scale	583	0.9503
HTMLDocument.prototype.captureEvents	121	0.9504
WebSocket.prototype.close	281	0.9537
Element.prototype.scrollIntoView	108	0.9537
Element.prototype.getClientRects	1064	0.9539
window.atob	4950	0.9541
URL.createObjectURL	1670	0.9545
HTMLInputElement.prototype.checkValidity	3894	0.9545
CSSStyleDeclaration.prototype.removeProperty	478	0.9561
CanvasRenderingContext2D.prototype.bezierCurveTo	185	0.9568
performance.onresourcetimingbufferfull	210	0.9571
window.postMessage	4762	0.9591
window.onunload	2505	0.9593
window.btoa	4146	0.9595
document.writeln	1928	0.9595
HTMLDocument.prototype.writeln	1928	0.9595
CustomEvent.prototype.initCustomEvent	1828	0.9612
Event.prototype.stopImmediatePropagation	390	0.9615
XPathResult.prototype.snapshotItem	162	0.963
HTMLCanvasElement.prototype.toDataURL	3447	0.9634
XMLHttpRequest.prototype.overrideMimeType	1196	0.964
CanvasRenderingContext2D.prototype.beginPath	3171	0.9647
CanvasRenderingContext2D.prototype.fillText	3584	0.9648
Crypto.prototype.getRandomValues	7048	0.9651
SVGGraphicsElement.prototype.getBBox	633	0.9652
window.name	3084	0.9653
HTMLCollection.prototype.item	3122	0.9664
Document.prototype.evaluate	359	0.9666
Worker.prototype.terminate	214	0.9673
CanvasRenderingContext2D.prototype.fill	3024	0.9676
HTMLDocument.prototype.close	4700	0.9679
document.domain	4364	0.9679
document.close	4700	0.9679
CanvasRenderingContext2D.prototype.fillRect	3562	0.968
CanvasRenderingContext2D.prototype.clearRect	3023	0.9682
window.content	537	0.9683
AudioContext.prototype.createOscillator	126	0.9683
CanvasRenderingContext2D.prototype.drawImage	3063	0.9696
CanvasRenderingContext2D.prototype.getImageData	2911	0.9698
CanvasRenderingContext2D.prototype.closePath	3021	0.9699
CanvasRenderingContext2D.prototype.rect	1169	0.9701
Navigator.prototype.javaEnabled	8356	0.9701
CanvasRenderingContext2D.prototype.arcTo	242	0.9711
NamedNodeMap.prototype.item	529	0.9716
window.open	4125	0.9716
document.onkeypress	955	0.9728
Event.prototype.initEvent	4570	0.9729
CanvasRenderingContext2D.prototype.createPattern	260	0.9731
Navigator.prototype.sendBeacon	2302	0.9735
CanvasRenderingContext2D.prototype.measureText	983	0.9736
Range.prototype.createContextualFragment	152	0.9737
Node.prototype.hasChildNodes	3250	0.9742
document.onclick	2464	0.9748
window.cancelAnimationFrame	3437	0.975
Range.prototype.setStartBefore	126	0.9762
Element.prototype.setAttributeNS	3215	0.9764
URL.revokeObjectURL	256	0.9766
document.onkeydown	2404	0.9771
CanvasRenderingContext2D.prototype.moveTo	2864	0.9777
window.onmessage	946	0.9778
Performance.prototype.getEntriesByName	3938	0.9782
CanvasRenderingContext2D.prototype.lineTo	2853	0.9786
XPathResult.prototype.iterateNext	140	0.9786
CanvasRenderingContext2D.prototype.stroke	2469	0.9789
Document.prototype.hasFocus	3890	0.9789
document.onmousemove	1019	0.9794
XMLSerializer.prototype.serializeToString	512	0.9805
CanvasRenderingContext2D.prototype.putImageData	2090	0.9813
window.onblur	750	0.9813
Element.prototype.remove	648	0.9815
document.onkeyup	872	0.9817
CanvasRenderingContext2D.prototype.restore	2872	0.9822
CanvasRenderingContext2D.prototype.save	2870	0.9822
HTMLTableRowElement.prototype.insertCell	346	0.9827
document.onreadystatechange	1896	0.9831
document.onmousedown	911	0.9835
Element.prototype.hasAttributes	183	0.9836
Performance.prototype.getEntries	1672	0.985
DOMTokenList.prototype.toggle	2077	0.9851
SVGPathElement.prototype.getTotalLength	140	0.9857
Element.prototype.matches	3907	0.9859
document.onmouseup	856	0.986
MessagePort.prototype.postMessage	3011	0.9861
document.head	454	0.9868
CanvasGradient.prototype.addColorStop	2069	0.987
CanvasRenderingContext2D.prototype.createLinearGradient	1978	0.9874
HTMLTableElement.prototype.insertRow	321	0.9875
CSSStyleSheet.prototype.deleteRule	2057	0.9883
CanvasRenderingContext2D.prototype.transform	2626	0.9893
CanvasRenderingContext2D.prototype.createRadialGradient	988	0.9899
CanvasRenderingContext2D.prototype.createImageData	1825	0.9901
NodeList.prototype.item	3076	0.9902
window.onfocus	2181	0.9917
CanvasRenderingContext2D.prototype.setTransform	2542	0.9921
CanvasRenderingContext2D.prototype.clip	2354	0.9924
Document.prototype.elementFromPoint	2194	0.9927
HTMLDocument.prototype.open	1861	0.993
document.open	1861	0.993
document.onscroll	727	0.9931
CanvasRenderingContext2D.prototype.quadraticCurveTo	2341	0.994
Document.prototype.createAttribute	2300	0.9948
Element.prototype.setAttributeNode	2285	0.9956
document.ondblclick	712	0.9972
window.onpagehide	752	0.9973
document.onwheel	705	0.9986
SVGTextContentElement.prototype.getComputedTextLength	1003	0.999
document.onmouseover	1652	0.9994
MessagePort.prototype.start	971	1
Blob.prototype.slice	105	1
FileReader.prototype.readAsArrayBuffer	106	1

[pes10k]

These numbers are taken from this work:

Peter Snyder, Lara Ansari, Cynthia Taylor, Chris Kanich, Browser feature usage on the modern web, Proceedings of the 2016 ACM on Internet Measurement Conference, 2016

https://www.cs.uic.edu/~psnyder/static/papers/Browser_Feature_Usage_on_the_Modern_Web.pdf

[luixxiul]

CC @diracdeltas