Use CreateCodegenMetrics in api_bp2build as well

The internals of CodegenMetrics was updated in aosp/2276671. Use the
new API to initialize an empty object to prevent a null pointer
exception in api_bp2uild.

Test: m api_bp2build
Change-Id: Iad9c38b9881da896171f1c6d4e49d4875acfaab8
diff --git a/cmd/soong_build/main.go b/cmd/soong_build/main.go
index 2cea5a5..0669f65 100644
--- a/cmd/soong_build/main.go
+++ b/cmd/soong_build/main.go
@@ -244,7 +244,7 @@
 	ninjaDeps = append(ninjaDeps, codegenContext.AdditionalNinjaDeps()...)
 
 	// Create soong_injection repository
-	soongInjectionFiles := bp2build.CreateSoongInjectionFiles(configuration, bp2build.CodegenMetrics{})
+	soongInjectionFiles := bp2build.CreateSoongInjectionFiles(configuration, bp2build.CreateCodegenMetrics())
 	absoluteSoongInjectionDir := shared.JoinPath(topDir, configuration.SoongOutDir(), bazel.SoongInjectionDirName)
 	for _, file := range soongInjectionFiles {
 		writeReadOnlyFile(absoluteSoongInjectionDir, file)