Heads up! This PR modifies the following files:

• @KiChjang: components/script/dom/bindings/refcounted.rs, components/script/dom/browsingcontext.rs, components/script/dom/bindings/trace.rs, components/script/script_thread.rs, components/script/dom/bindings/js.rs, components/script/script_runtime.rs

Warning

• These commits modify unsafe code. Please review it carefully!
• These commits modify script code, but no tests are modified. Please consider adding a test!

-S-awaiting-review +S-needs-code-changes

Reviewed 5 of 5 files at r1, 1 of 1 files at r2, 1 of 1 files at r3.
Review status: all files reviewed at latest revision, 2 unresolved discussions.

components/script/dom/browsingcontext.rs, line 283 [r3] (raw file):

unsafe extern fn trace(trc: *mut JSTracer, obj: *mut JSObject) {
    let this = GetProxyExtra(obj, 0).to_private() as *const BrowsingContext;
    if this.is_null() { return; } // GC during obj creation

if this.is_null() {
    // GC during object creation.
    return;
}

components/script/dom/bindings/js.rs, line 111 [r1] (raw file):

    fn trace(&self, trc: *mut JSTracer) {
        trace_reflector(trc,
                        &format!("for {} on heap", unsafe { type_name::<T>() }),

I think this is going to be too expensive.

Comments from Reviewable

New code was committed to pull request.

@bors-servo r+

Reviewed 4 of 4 files at r4, 1 of 1 files at r5, 1 of 1 files at r6.
Review status: all files reviewed at latest revision, all discussions resolved.

Comments from Reviewable

📌 Commit 929d8c0 has been approved by Ms2ger

⌛ Testing commit 929d8c0 with merge fc45b89...

💔 Test failed - windows

@bors-servo retry

• The annoying git

⚡ Previous build results for linux-dev, mac-dev-unit are reusable. Rebuilding only android, arm32, arm64, linux-rel, mac-rel-css, mac-rel-wpt, windows...

💔 Test failed - linux-rel

/home/servo/buildbot/slave/linux-rel/build/components/script/dom/bindings/js.rs:113:14: 113:23 error: unresolved name `trace_str` [E0425]
/home/servo/buildbot/slave/linux-rel/build/components/script/dom/bindings/js.rs:113             &trace_str[..]
                                                                                                 ^~~~~~~~~

@bors-servo r-

New code was committed to pull request.

@bors-servo r=Ms2ger

📌 Commit a85e659 has been approved by Ms2ger

⌛ Testing commit a85e659 with merge 91cabf8...

☀️ Test successful - android, arm32, arm64, linux-dev, linux-rel, mac-dev-unit, mac-rel-css, mac-rel-wpt, windows