Have ConvertWBp2build use Bp2buildMutatorContext

This no-op refactoring facilitates some upcoming functional changes for
"bp2build allowlist v2". The work requires that the bp2build conversion
mutator be changed from a TopDown mutator to a BottomUp mutator.
Refactoring all bp2build-related methods so that they use Bp2buildMutatorContext
makes it easier to make this functional change without touching tens of
files and multiple projects.

Bug: 285631638
Test: m bp2build
Change-Id: I3d1ef3064146e959c6f0dc315350fc9764bf2bd2
diff --git a/android/bazel.go b/android/bazel.go
index e764b18..8634dab 100644
--- a/android/bazel.go
+++ b/android/bazel.go
@@ -162,7 +162,7 @@
 	// Modules must implement this function to be bp2build convertible. The function
 	// must either create at least one Bazel target module (using ctx.CreateBazelTargetModule or
 	// its related functions), or declare itself unconvertible using ctx.MarkBp2buildUnconvertible.
-	ConvertWithBp2build(ctx TopDownMutatorContext)
+	ConvertWithBp2build(ctx Bp2buildMutatorContext)
 
 	// namespacedVariableProps is a map from a soong config variable namespace
 	// (e.g. acme, android) to a map of interfaces{}, which are really