coverage: Update coverage utils to handle rust coverage artifacts

At present, we only have CPP artifacts. Update the zero coverage and
coverage handlers to understand rust coverage artifacts.

BUG=b:3892792
TEST=./run_tests service/test_unittest.py and ./run_tests
utils/code_coverage_util_unittest.py

Change-Id: I39226b1f9e0e1eb030e21f95b35dd43728141ff2
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/3911182
Commit-Queue: Srinivas Hegde <srinivashegde@google.com>
Reviewed-by: Sergey Frolov <sfrolov@google.com>
Tested-by: Srinivas Hegde <srinivashegde@google.com>
Reviewed-by: Kshitij Pancholi <panchok@google.com>
diff --git a/api/controller/test.py b/api/controller/test.py
index bb37ea2..2a65c11 100644
--- a/api/controller/test.py
+++ b/api/controller/test.py
@@ -449,6 +449,9 @@
         in_proto.ArtifactType.CODE_COVERAGE_LLVM_JSON: functools.partial(
             test.BundleCodeCoverageLlvmJson, build_target.name
         ),
+        in_proto.ArtifactType.CODE_COVERAGE_RUST_LLVM_JSON: functools.partial(
+            test.BundleCodeCoverageRustLlvmJson, build_target.name
+        ),
         in_proto.ArtifactType.HWQUAL: functools.partial(
             test.BundleHwqualTarball,
             build_target.name,