Animation Pipeline: Main Thread to Compositor

The sources provide an extensive architectural overview of the Chromium animation pipeline, detailing the complex process required to accelerate animations by moving them off the main thread onto the compositor thread (cc). The explanation outlines the flow, starting when an animation is initiated in the Blink renderer via classes like Animation and KeyframeEffect, especially if the animation targets compositor-capable properties like transform or opacity. This main thread state is prepared for transfer during the PreCommit phase, where the main thread's AnimationHost creates corresponding compositor objects. The sources then explain the Commit process, where the CommitState structure facilitates the safe synchronization of this animation data to the compositor thread's AnimationHost and ElementAnimations object. Finally, the text describes how animations run on the compositor, ticking every frame and applying values directly to the property trees before sending synchronization events back to Blink regarding start and completion times.