Chromium Animation Keyframe Snapshotting and Native Paint Worklets

The provided sources describe the specialized native paint worklet architecture used by Chromium to animate properties like background-color on the compositor thread. Unlike traditional properties that use keyframe snapshots to cache resolved values, this system generates a PaintWorkletInput during the paint phase to store color data and timing functions. The compositor then drives a simplified progress animation from 0 to 1, allowing a native C++ definition to interpolate colors and perform rasterization independently of the main thread. This approach bypasses the standard Blink style resolution for every frame, significantly improving performance for paint-heavy properties. If an animation’s parameters change, the system triggers a repaint to refresh the input data rather than updating ordinary compositor keyframes. Ultimately, this framework provides a robust handoff mechanism that enables complex painting tasks to behave like hardware-accelerated animations.