Chromium Blog: July 2015

Chrome 45 Beta: New ES2015 features, service worker improvements, and media controls

Monday, July 27, 2015

The newest Chrome Beta channel release includes new JavaScript language features, an improved audio experience on Android, and a large number of minor API improvements and deprecations. Unless otherwise noted, changes described below apply to Chrome for Android, Windows, Mac, Linux, and Chrome OS. New ES2015 features Over the past year Chrome has shipped a number of new JavaScript features defined in the ES2015 specification (formerly known as ES6), a major update to JavaScript that allows developers to write application logic that is easier to read, more powerful, and more memory efficient than ever before.
Chrome 45 includes a set of new ES2015 features including arrow functions, new methods on Array, new methods on TypedArray, and Object.assign(). Service worker improvements Chrome 40 introduced support for service workers, enabling developers to build high performance sites that work offline. This release includes a number of improvements:

Developers are now able to measure their service worker’s performance using the User Timing and Resource Timing APIs.

Service workers used exclusively to send push notifications are now kept up-to-date correctly and developers can also use the new update method to manually trigger an update check.

Sites can now use getRegistrations() to access all the service workers whose scope matches the current page.

Finally, in a breaking change, messages sent via Client.postMessage() now fire an event on navigator.serviceWorker instead of the window object. Media controls in Android notifications

Playback controls for currently-playing audio are shown in the notification tray and on the lock screen
On Android, native apps can show media controls in a system notification when playing audio, making it easy for users to control audio while multitasking. Chrome 45 brings this capability to the web by showing a notification with media controls when audio is playing in web content. The controls will automatically show up when <audio> or <video> tags play audio longer than 5 seconds. Other updates in this release

Sites can now customize the vibration triggered when showing a notification on Android.

Chrome’s implementation of the Push API has undergone several minor breaking changes to keep up to date with the evolving specification.

Sites using promoted add to home screen can now programmatically control the timing of the banner.

The rotationAngle attribute of Touch objects is no longer prefixed, making it easier for sites to understand the geometry of the user's touch with cross-browser code.

To improve scroll performance on pages with heavy mouse handlers or :hover styles, Chrome no longer sends mouse position updates when the user is scrolling with a trackpad or scrollwheel.

Chrome now immediately prefetches all HTML imports referenced by a page instead of waiting for scripts included higher in the document to finish executing, improving performance.

Sites can now include 3rd-party resources on their site with reduced security risk by using a hash to ensure the integrity of 3rd-parties resources.

To reduce the risk of certain types of attack, the 'self' source defined by Content Security Policy now excludes blob and filesystem URLs.

The logjam attack is fixed in this release by deprecating the use of keys smaller than 1024 bits in Diffie-Hellman key exchanges, which may require developers to update their server’s TLS configuration.

To improve cross-browser compatibility and specification compliance, CSSUnknownRule and CSSKeyframesRule.insertRule() are now deprecated with the latter now replaced by CSSKeyframesRule.appendRule().

Sites using SMIL will now trigger deprecation warnings in the console, encouraging them to migrate to CSS Animations and Web Animations.

This release deprecates both multiple shadow roots and shadow-piercing deep selectors following a unanimous decision by browser vendors at the Web Components April 2015 meeting.

The MediaStream attributes label and ended are now deprecated in favor of id and active, while the stop() method is deprecated in favor of MediaStreamTrack.stop().

Update: The User Timing and Resource Timing APIs are unfortunately not exposed to service workers in this release, but should be available in Chrome 46. As always, visit chromestatus.com/features for a complete overview of Chrome’s developer features, and circle +Google Chrome Developers for more frequent updates.Posted by Andreas Rossberg, Software Engineer and ECMAScript Evangelizer

Exploring the Physical Web with Chrome for iOS

Wednesday, July 22, 2015

Today’s connected world is full of opportunities for people to digitally interact with their surroundings on the fly. For example, smart parking meters let users pay through the cloud. But for developers, it’s often difficult to build contextual experiences that people can easily access. Even with the prevalence of smartphones, users are reluctant to install an app or even type a URL while on the go.
The Physical Web is an open source approach to help you build contextual interactions that people can discover and use with less friction. A few months ago, Chrome for iOS added a Today widget to let users open a new tab or do a voice search right from the Notification Center. The new Chrome for iOS integrates the Physical Web into the Chrome Today widget, enabling users to access an on-demand list of web content that is relevant to their surroundings.

It’s easy to make your content discoverable via the Physical Web using Eddystone, an open Bluetooth Low Energy beacon format announced last week. Eddystone supports multiple frame types for different use cases. The Physical Web displays content that is broadcasted using Eddystone-URL, the beacon frame type designed to convey compressed URLs. You can add your content to the Physical Web by simply configuring a beacon that supports Eddystone-URL to transmit your URL of choice.
When users who have enabled the Physical Web open the Today view, the Chrome widget scans for broadcasted URLs and displays these results, using estimated proximity of the beacons to rank the content. You can learn more about the types of user experiences that the Physical Web enables by visiting our cookbook and joining the open source community on GitHub.
The new Chrome for iOS is an early exploration in enabling users to access the Physical Web in their day-to-day mobile experiences. As the ecosystem grows, we’ll continue to explore new ways to bring the Physical Web to users’ fingertips. We’re looking forward to seeing the new contextual experiences you’ll build.
Posted by Jake Leichtling, Physical Web Explorer

Revving up JavaScript performance with TurboFan

Tuesday, July 7, 2015

The JavaScript ecosystem is evolving in several promising ways. There have been mainstream standards advancements like the recent approval of ECMAScript 2015, as well as early-stage experiments like Strong Mode, to name a few. Balancing the needs of these new directions demands a flexible just-in-time compiler, and we've been hard at work on a brand new compiler for V8, codenamed "TurboFan." Since Chrome 41, TurboFan has been enabled for certain types of code, speeding up traditional content as well as improving performance for new language features.
TurboFan was built from the ground up with many unique capabilities in mind. It optimizes more code than the previous optimizing compiler, supports flexible and dynamic optimization modes, and enables easier contributions and maintenance. Thanks to these features and more, we've turned on TurboFan for some types of code that were challenging for our previous compiler to optimize, such as asm.js, class literals, with scopes, computed property names and for-of loops. TurboFan already shows promising performance results, including a 29% increase on the zlib score of the Octane benchmark.

Over the coming months, we expect to enable TurboFan for more and more types of JavaScript, with the eventual goal of entirely replacing our existing CrankShaft compiler. As it rolls out, developers' code will automatically get these free speedups with no changes needed. Stay tuned for future progress. Posted by Ben L. Titzer, Software Engineer and TurboFan Mechanic

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Chromium Blog

Chrome 45 Beta: New ES2015 features, service worker improvements, and media controls

Exploring the Physical Web with Chrome for iOS

Revving up JavaScript performance with TurboFan

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