Navigator.Plugins() and Navigator.MimeTypes() will only report the presence of Flash Player if the user has indicated that the domain should execute Flash.
Implemented, currently in trials on Chrome 55+.
Users or developers who wish to enable HTML5 by Default can go to chrome://flags/#prefer-html-over-flash, select “Enabled” and then restart Chrome.
With Chrome 55 Stable, HTML5 by Default is enabled for 1% of Chrome users. The feature is also enabled for 50% of Chrome 56 Beta users, with plans to increase to 100% with Chrome 56 Stable at the beginning of February.
Flash prompting will only be enabled for sites whose Site Engagement Index (SEI) is below a certain threshold. For Chrome 55, starting in January 2017 prompts will only appear for sites where the user’s SEI is less than 1. That threshold will increase to 100 through October 2017, when all Flash sites will require an initial prompt. One exception is Chrome 56 Beta, which will use a fixed threshold of 30 to allow developers to experiment with the feature. As a reminder, users will only be prompted once per site.
Here’s a summary of thresholds and % of users:
To test HTML5 by Default, we recommend using Chrome 56 Beta which uses a fixed Site Engagement Score threshold of 30. To ensure that the feature is enabled, please navigate to chrome://flags/#prefer-html-over-flash, select “Enabled” and then restart Chrome.To see your site engagement, please visit chrome://site-engagement. Note that for Chrome 56 Beta, the threshold will fixed at 30.
We are removing the final restriction for Plugin Power Savings Mode, which permitted small (5x5) content, hosted on the same origin, to run.
The exception was meant to be a temporary relief for smaller developers, for features that are well now very supported by the web platform (e.g. clipboard access, audio streams, etc...).
Chrome pauses non-essential(1) Flash Content, by replacing the plugin content with a static image preview and a play button overlayed. Users can re-enable this content by clicking play.
(1) - Non-essential content being smaller than 300x400 pixels or smaller than 5x5 pixels.
Limit Flash Playbacks to visible main body content (e.g. video, games, etc...) and still permit streaming audio services to function.
A further restriction to Plugin Power Savings Mode that removes the ability to run 5x5 or smaller content, from a different origin.
Much of this content (5x5 below) was used for viewability detection (i.e. to see if an ad was on that page), requiring Chrome to spin up a relatively expensive (in terms of performance) Flash process in order for the site to infer viewability.
With the introduction of Intersection Observer in Chrome 51, which added platform support for this use case, there was no longer a need to continue granting this exception.
We left an exception for "same origin" 5x5 Flash content, to give smaller sites (e.g. using things like clipboard access) time to migrate.
Chrome to automatically use the HTML5 content of a YouTube embed when the Flash one is used.
This will allow the long tail of websites that never updated to the HTML5 embeds to no longer require Flash for Chrome users, thus reducing overall usage of Flash in Chrome.
Chrome to exclusively use the component updater to distribute Flash Player, and separating it from Chrome's default distribution bundle.
Enable Chrome to rapidly distribute Flash Player updates, without re-building the core product, making it easier to match Adobe's monthly release cadence.
This feature was fundamentally technology gated, requiring development of in-line on-demand Flash component installs, differential component updates, and building out special serving infrastructure.