Chromium Blink's Layer Recycle Tree Optimization

The sources provide an extensive technical explanation of the Chromium/Blink rendering pipeline, focusing specifically on the compositor's layer trees and a performance optimization known as the Recycle Tree. Modern web rendering is detailed as a multi-phase process involving the DOM Tree, style, layout, and ultimately, compositing, which operates on a separate thread using Active, Pending, and Recycle Tree structures. The primary function of the Recycle Tree is to act as a cache of old layer objects (LayerImpls) from the previous frame, allowing the compositor to reuse them during the next commit instead of allocating new objects, which drastically reduces memory churn and speeds up dynamic updates like animations. This mechanism ensures that the compositor can efficiently mirror changes originating from the main thread's style invalidation and layout calculations, thereby maintaining high frame rates and preventing jank during continuous web interaction.