| The page load metrics subsystem captures and records UMA metrics related to |
| page loading. This includes page timing metrics, such as time to first |
| paint, as well as page interaction metrics, such as number of page loads |
| aborted before first paint. |
| |
| The page load metrics subsystem is shared by Chrome and WebView, but not |
| supported on iOS, as it requires hooks into Blink for page timing metrics that |
| are unavailable on iOS. |
| |
| This component has the following structure: |
| - components/page_load_metrics/browser: browser process code |
| - components/page_load_metrics/common/: code shared by browser and renderer, such |
| as IPC messages |
| - components/page_load_metrics/renderer : renderer process code |
| |
| For additional information on this subsystem, see |
| https://docs.google.com/document/d/1HJsJ5W2H_3qRdqPAUgAEo10AF8gXPTXZLUET4X4_sII/edit |