Build API config: Use a proto-based configuration

Switch the Build API to use a proto configuration rather than
CLI options. This provides cleaner backwards compatibility for
the build api itself.

BUG=chromium:1040978
TEST=run_tests

Change-Id: I515271b4244c354c38538b30dcc1cfa07517f821
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/chromite/+/1994725
Tested-by: Alex Klein <saklein@chromium.org>
Reviewed-by: Will Bradley <wbbradley@chromium.org>
Commit-Queue: Alex Klein <saklein@chromium.org>
diff --git a/api/api_config_unittest.py b/api/api_config_unittest.py
index a616af9..ebbf925 100644
--- a/api/api_config_unittest.py
+++ b/api/api_config_unittest.py
@@ -14,30 +14,17 @@
 class ApiConfigTest(cros_test_lib.TestCase):
   """ApiConfig tests."""
 
-  def test_incompatible_arguments(self):
-    """Test incompatible argument checks."""
-    # Can only specify True for one of validate_only, mock_call, and mock_error.
-    # Enumerating them was unnecessary, but it's only 4 cases.
-    with self.assertRaises(AssertionError):
-      ApiConfig(validate_only=True, mock_call=True)
-    with self.assertRaises(AssertionError):
-      ApiConfig(validate_only=True, mock_error=True)
-    with self.assertRaises(AssertionError):
-      ApiConfig(mock_call=True, mock_error=True)
-    with self.assertRaises(AssertionError):
-      ApiConfig(validate_only=True, mock_call=True, mock_error=True)
-
   def test_do_validation(self):
     """Sanity check for the do validation property being True."""
     # Should validate by default, and when only doing validation.
     config = ApiConfig()
     self.assertTrue(config.do_validation)
-    config = ApiConfig(validate_only=True)
+    config = ApiConfig(call_type=ApiConfig.CALL_TYPE_VALIDATE_ONLY)
     self.assertTrue(config.do_validation)
 
   def test_no_do_validation(self):
     """Sanity check for skipping validation for mock calls."""
-    config = ApiConfig(mock_call=True)
+    config = ApiConfig(call_type=ApiConfig.CALL_TYPE_MOCK_SUCCESS)
     self.assertFalse(config.do_validation)
-    config = ApiConfig(mock_error=True)
+    config = ApiConfig(call_type=ApiConfig.CALL_TYPE_MOCK_FAILURE)
     self.assertFalse(config.do_validation)