Today there are more tools to measure different parts of the performance of the browser, among other things, SunSpider (WebKit / Apple), V8 Benchmark Suite (Google) and Dromaeo (Mozilla). But common to the most common is that they are made of a browser vendor. It is therefore difficult to see these tests as entirely independent.
Another aspect of the tests is that they seldom helps web developers to optimize the performance of their Web applications.
W3C announced yesterday that the organization has created a new working group to work with web perfomance. The mission of Web Performance Working Group, the group is called, is to provide methods for measuring aspects of application performance features and APIs in web browsers.

W3C writes in a press release of as web browsers and their underlying engines are becoming more powerful and feature rich functionality, web developers create more sophisticated applications where application performance is becoming more and more important.
W3C believes that developers have a need to establish and understand performance characteristics to their applications, using well-defined methods with a focus on interoperability.
Group results will be relevant for both PC and mobile browsers, but also for other communities without the traditional browsers. The results shall be in accordance with the Web technologies designed in other W3C working groups, including HTML, CSS, webapps, DAP and SVG.