Identify relevant key performance metrics and measurements

As relevant metrics we identified those already collected by the devtools of most browsers: dom content loaded first contentful paint first pain on load Additionally, we’re including an experimental set of network metrics, which take all requests performed by the browser into account to compute: finish time: time taken to complete all requests since PerformanceTiming.fetchStart request count: the number of requests issued transfer size decoded body size However, some requests seem to be ignored and not included in the performance entries ( https://developer.mozilla.org/en-US/docs/Web/API/Performance/getEntries ) on Chrome, which renders this data incomplete in this browser. Furthermore, transfer size and decoded body size cannot be retrieved on Safari and Edge. We are also storing a set of custom performance marks and measurements, which are aligned with what we want to measure: [mark] nuxeo-app.ready : marks the moment when the nuxeo-app element is ready [mark] nuxeo-app.page-changed : marks the last moment where there was a page switch (not set when the first page is loaded, since there is not transition) [mark] nuxeo-app.page-loaded : marks the moment where the last dom-change event was fired from within the current page, .i.e, the last moment in which there were changes in the page [measurement] <page-name>.dom-changed : a measurement between the moment in which the last dom-change event is fired from within the current page and the last page-change mark (or PerformanceTiming.fetchStart if undefined ) - this is mostly helpful for development and debugging purposes We added these metrics to the performance analyzer added in NXP-25303 . You can try these out by running: Nuxeo.Performance.report({networkStats: true });