Bug 1809568 - Part 2: Provide GetNaturalBaselineBOffset with baseline export context. r=emilio

Some baseline exports are context-sensitive. One example: In line-layout scenario,
the last baseline of a scroll container is always the margin-end. In other (e.g.
flex, grid) scenarios, it's the border-box clamped offset to the last line in the
container.
This enables the required 3 different behaviours for `inline-block` scroll containers
for 3 different `baseline-source` values:
- `auto`: Last baseline, margin-end
- `first`: Border-box clamped offset to the first line
- `last`: Border-box clamped offset to the last line

Differential Revision: https://phabricator.services.mozilla.com/D173886

layout/generic/nsColumnSetFrame.cpp

@@ -1298,10 +1298,12 @@ void nsColumnSetFrame::AppendDirectlyOwnedAnonBoxes(
 }
 
 Maybe<nscoord> nsColumnSetFrame::GetNaturalBaselineBOffset(
-    WritingMode aWM, BaselineSharingGroup aBaselineGroup) const {
+    WritingMode aWM, BaselineSharingGroup aBaselineGroup,
+    BaselineExportContext aExportContext) const {
   Maybe<nscoord> result;
   for (const auto* kid : mFrames) {
-    auto kidBaseline = kid->GetNaturalBaselineBOffset(aWM, aBaselineGroup);
+    auto kidBaseline =
+        kid->GetNaturalBaselineBOffset(aWM, aBaselineGroup, aExportContext);
     if (!kidBaseline) {
       continue;
     }