T10.1: with the vendored `HardwareOffscreenContext` (048c5df) and the
host-level kind dispatch (a7d3e89) in place, the sidecar binary
still ignored the rendering context kind — every spawn was wired to
the software path regardless of how the host process was built. This
commit threads the choice end-to-end:
* `ely_servo_sidecar` learns a `--rendering-context [software|
hardware]` flag on its `live` subcommand. `LiveArgs` carries
the parsed `RenderingContextKind` (defaulting to `Software` so
existing invocations stay bit-identical) and `live.rs::run_live`
routes it through to `SoftwareServoHost::new_with_config_dir_and_kind`.
Unknown values produce a typed
`SidecarArgsError::InvalidRenderingContext`; a missing value
after the flag produces the existing `MissingArgumentValue`.
* `ely_app` reads `ELY_SERVO_RENDERING_CONTEXT` (with values
`software` / `hardware`, case-insensitive) and, if set, appends
`--rendering-context VALUE` to the sidecar command line.
Unset or unrecognised values fall through to the sidecar's own
software default — a stale env var or a typo never breaks the
browser startup. The sidecar arg parser is the source of truth
for legality of explicit values; the env helper only gates
which values reach it.
* Five new unit tests in `args::tests` pin the new parse paths:
default-is-software, explicit-software, explicit-hardware,
bogus-value-rejected, missing-value-rejected. Run via
`cargo test -p ely_servo_host --features servo-engine --bin
ely_servo_sidecar` and now hit alongside the five existing
snapshot tests for 10 passes.
End-to-end perf expectation: with the sidecar binary built using
`--features servo-engine,hardware-render` and the env var set to
`hardware`, every spawned sidecar webview rasterises through the
real GPU adapter (via the vendored
`HardwareOffscreenContext`/surfman/CGL chain on macOS). The host
still reads back RGBA into a `Vec<u8>` for the existing pipe
protocol; the IOSurface zero-copy bridge that deletes that
read-back is T10.2–T10.5 in docs/t10-iosurface-plan.md and lands
in subsequent commits.
cargo test --bin ely_app: 120 passed, 0 failed, 2 ignored.
cargo test -p ely_servo_host --features servo-engine --bin ely_servo_sidecar: 10 passed.
cargo test -p ely_servo_host --features servo-engine --test sidecar: 9 passed.
cargo test -p ely_servo_host --features servo-engine,hardware-render --test hardware_rendering_context: 1 passed.
ZacharyZhang-NY
18fd20b577