package_info.SplitCPV: Refactor usages to parse.

Refactor another cluster of SplitCPV and the corresponding CPV usages.

BUG=b:187792048
TEST=run_tests

Change-Id: I08bec55f983489ef52241d0d2d8e492d4d6c578a
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3152618
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Chris McDonald <cjmcdonald@chromium.org>
Reviewed-by: Sergey Frolov <sfrolov@google.com>
Commit-Queue: Alex Klein <saklein@chromium.org>
diff --git a/api/controller/sysroot.py b/api/controller/sysroot.py
index 4627535..ec89c34 100644
--- a/api/controller/sysroot.py
+++ b/api/controller/sysroot.py
@@ -186,9 +186,9 @@
     sysroot.InstallToolchain(build_target, target_sysroot, run_configs)
   except sysroot_lib.ToolchainInstallError as e:
     # Error installing - populate the failed package info.
-    for package in e.failed_toolchain_info:
-      package_info = output_proto.failed_packages.add()
-      controller_util.CPVToPackageInfo(package, package_info)
+    for pkg_info in e.failed_toolchain_info:
+      package_info_msg = output_proto.failed_packages.add()
+      controller_util.serialize_package_info(pkg_info, package_info_msg)
 
     return controller.RETURN_CODE_UNSUCCESSFUL_RESPONSE_AVAILABLE
 
@@ -252,9 +252,9 @@
       return controller.RETURN_CODE_COMPLETED_UNSUCCESSFULLY
 
     # We need to report the failed packages.
-    for package in e.failed_packages:
-      package_info = output_proto.failed_packages.add()
-      controller_util.CPVToPackageInfo(package, package_info)
+    for pkg_info in e.failed_packages:
+      package_info_msg = output_proto.failed_packages.add()
+      controller_util.serialize_package_info(pkg_info, package_info_msg)
 
     return controller.RETURN_CODE_UNSUCCESSFUL_RESPONSE_AVAILABLE