Migrate away from compilation_outputs.files_to_compile

The same information is available in other fields.

This prevents regression when compilation_outputs are rewritten to Starlark.

PiperOrigin-RevId: 805762499
Change-Id: I7ea897a80dbb28c3542838c735c6a7395de818cf
diff --git a/cc/common/cc_helper.bzl b/cc/common/cc_helper.bzl
index 84de752..2915fbc 100644
--- a/cc/common/cc_helper.bzl
+++ b/cc/common/cc_helper.bzl
@@ -180,10 +180,16 @@
     process_hdrs = cpp_configuration.process_headers_in_dependencies()
     use_pic = cc_toolchain.needs_pic_for_dynamic_libraries(feature_configuration = feature_configuration)
     output_groups_builder["temp_files_INTERNAL_"] = compilation_outputs.temps()
-    files_to_compile = compilation_outputs.files_to_compile(
-        parse_headers = process_hdrs,
-        use_pic = use_pic,
-    )
+    if hasattr(compilation_outputs, "files_to_compile"):
+        files_to_compile = compilation_outputs.files_to_compile(
+            parse_headers = process_hdrs,
+            use_pic = use_pic,
+        )
+    else:
+        files_to_compile = compilation_outputs.pic_objects if use_pic else compilation_outputs.objects
+        if process_hdrs:
+            files_to_compile = files_to_compile + compilation_outputs.header_tokens()
+        files_to_compile = depset(files_to_compile)
     output_groups_builder["compilation_outputs"] = files_to_compile
     output_groups_builder["compilation_prerequisites_INTERNAL_"] = _collect_compilation_prerequisites(ctx = ctx, compilation_context = compilation_context)
     output_groups_builder["module_files"] = depset(compilation_outputs.module_files())