The source provides an extensive technical overview of the RasterSource concept within the Chromium browser's rendering pipeline. This component serves as a crucial, immutable, and thread-safe container for recorded drawing instructions, bridging the gap between the main thread (where Blink paints content) and the compositor/GPU threads (where pixels are generated). The text details how RasterSource is created as a snapshot of a RecordingSource during the commit phase and is then used by the TileManager to efficiently rasterize layer content into small tiles using either CPU (software) or GPU acceleration. The document emphasizes that this deferred and parallelized approach, enabled by RasterSource, is vital for smoother scrolling, partial updates, and overall performance optimization through intelligent invalidation and caching strategies.
