API Deprecations and Removals in Chrome 57
In nearly every version of Chrome, we see a significant number of updates and improvements to the product, its performance, and also capabilities of the Web Platform. This article describes the deprecations and removals in Chrome 57, which is in beta as of early February. This list is subject to change at any time.
Remove BluetoothDevice.uuids attribute
BluetoothDevice.uuids attribute is being removed to bring the Web Bluetooth API in line with the current specification. You can retrieve all allowed GATT services by calling device.getPrimaryServices().
Remove key generation element
Since Chrome 49,
<keygen>'s default behavior has been to return the empty string, unless a permission was granted to this page. IE/Edge do not support
<keygen> and have not indicated public signals to support
<keygen>. Firefox already gates
<keygen> behind a user gesture, but is publicly supportive of removing it. Safari ships
<keygen> and has not expressed public views regarding its continued support. With Chrome 57, this element is removed.
Remove prefixed resource timing buffer-management API
Two methods and an event handler,
onwebkitresourcetimingbufferfull are obsolete and vendor-specific. The standard versions of these APIs have been supported in since Chrome 46, and the prefixed functions were deprecated in that version as well. These features were originally implemented in WebKit, but Safari has not enabled them. Firefox, IE 10+, and Edge have only unprefixed version of the API. Therefore the webkit versions are being removed.
Remove ServiceWorkerMessageEvent in favor of using MessageEvent
The HTML spec extended
MessageEvent to allow
ServiceWorker as a type for the
client.postMessage() and creation of custom message events are changed to use
MessageEvent instead of
ServiceWorkerMessageEvent is removed.
Remove webkit-prefixed IndexedDB global aliases
IndexedDB entry point and global constructors were exposed with
webkit prefixes somewhere around Chrome 11. The non-prefixed versions were added in Chrome 24 and the prefixed versions were deprecated in Chrome 38. The following interfaces are affected:
webkitIndexedDB(main entry point)
webkitIDBKeyRange(non-callable global constructor, but has useful static methods)
webkitIDBTransaction(non-callable global constructors)
WebAudio: Remove prefixed AudioContext and OfflineAudioContext
Chrome has supported
WebAudio since mid 2011, including
OfflineAudioContext was added the following year. Given how long the standard interfaces have been supported and Google's long-term goal of removing prefixed features, the prefixed versions of these interfaces have been deprecated since late 2014 and are now being removed.
Deprecate and remove webkitCancelRequestAnimationFrame
webkitCancelRequestAnimationFrame() method is a an obsolete, vendor-specific API and the standard
cancelAnimationFrame() has long been supported in Chromium. Therefore the webkit version is being removed.
Deprecate case-insensitive matching for usemap attribute
usemap attribute was formerly defined as caseless. Unfortunately implementing this was complicated enough that no browsers implemented it correctly. Research suggested that such complicated algorithm is unnecessary, and even ASCII case-insensitive matching is unnecessary.
Consequently, the specification was updated so that case-sensitive matching is applied. The old behavior is deprecated in Chrome 57, with removal expected in Chrome 58.
Deprecate FileReaderSync in service workers
The Service Worker spec has always had the (non-normative) note that "any type of synchronous requests must not be initiated inside of a service worker", to avoid blocking the service worker. Blocking the service worker would block all network requests from controlled pages. Unfortunately, the
FileReaderSync API has long been available in service workers.
Currently only Firefox and Chrome expose
FileReaderSync in service workers. There's agreement from Firefox in the spec discussion that this should be fixed. Removal is anticipated in Chrome 59.
Deprecate legacy caller for HTMLEmbedElement and HTMLObjectElement
That an interface has a legacy caller means that an instance can be called as a function. Currently,
HTMLObjectElement support this functionality. In Chrome 57 this ability is deprecated. After removal, which is expected in Chrome 58, calling will throw an exception.
This change brings Chrome in line with recent spec changes. The legacy behavior is not supported in Edge or Safari, and it is being removed from Firefox.
Deprecate RTCRtcpMuxPolicy of "negotiate"
rtcpMuxPolicy is used by Chrome to specify its preferred policy regarding use of RTP/RTCP multiplexing. In Chrome 57, we changed the default
rtcpMuxPolicy to "require" and deprecated "negotiate" for following reasons:
- Non-muxed RTCP uses extra network resources.
- Removing "negotiate" will make the API surface simpler, since an "RtpSender"/"RtpReceiver" will then only ever have a single transport.
In Chrome 57, "negotiate" is deprecated. We believe this is a non-breaking change since the user will get a deprecation message and
RTCPeerConnection can still be created. Removal is in Chrome 63.
Deprecate support for embedded credentials in subresource requests
Hard-coding credentials into subresource requests is problematic from a security perspective, as it's allowed hackers to brute-force credentials in the past. These dangers are exacerbated for credentialed subresource requests that reach into internal IP ranges (your routers, etc.). Given the low usage, closing this (small) security hole seems quite reasonable.
Developers can embed resources that do not require basic/digest auth, relying instead on cookies and other session management mechanisms.