Add isolated_server arg to builders.builder().

This allows us to pass in isolatedserver host to https://source.chromium.org/chromium/infra/infra/+/master:recipes-py/recipe_modules/isolated/api.py

Bug: 894045
Change-Id: I8be297ae601e45f1cf9b5422c4a5d996cf4e5662
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2395300
Commit-Queue: Ye Kuang <yekuang@google.com>
Reviewed-by: Takuto Ikuta <tikuta@chromium.org>
Cr-Commit-Position: refs/heads/master@{#804722}

infra/config/dev/subprojects/chromium/ci.star

@@ -55,11 +55,7 @@ def ci_builder(*, name, **kwargs):
         resultdb_bigquery_exports = [resultdb.export_test_results(
             bq_table = "luci-resultdb-dev.chromium.ci_test_results",
         )],
-        properties = {
-            "$recipe_engine/isolated": {
-                "server": "https://isolateserver-dev.appspot.com",
-            },
-        },
+        isolated_server = "https://isolateserver-dev.appspot.com",
         **kwargs
     )
 

infra/config/lib/builders.star

@@ -232,6 +232,15 @@ def _code_coverage_property(
 
     return code_coverage or None
 
+def _isolated_property(*, isolated_server):
+    isolated = {}
+
+    isolated_server = defaults.get_value("isolated_server", isolated_server)
+    if isolated_server:
+        isolated["server"] = isolated_server
+
+    return isolated or None
+
 ################################################################################
 # Builder defaults and function                                                #
 ################################################################################
@@ -263,6 +272,7 @@ defaults = args.defaults(
     coverage_exclude_sources = None,
     coverage_test_types = None,
     resultdb_bigquery_exports = [],
+    isolated_server = None,
 
     # Provide vars for bucket and executable so users don't have to
     # unnecessarily make wrapper functions
@@ -303,6 +313,7 @@ def builder(
         coverage_exclude_sources = args.DEFAULT,
         coverage_test_types = args.DEFAULT,
         resultdb_bigquery_exports = args.DEFAULT,
+        isolated_server = args.DEFAULT,
         **kwargs):
     """Define a builder.
 
@@ -401,6 +412,9 @@ def builder(
       * resultdb_bigquery_exports - a list of resultdb.export_test_results(...)
         specifying parameters for exporting test results to BigQuery. By default,
         do not export.
+      * isolated_server - a string indicating the host of the isolated server.
+        Will be incorporated into the '$recipe_engine/isolated' property. By
+        default, this is None.
       * kwargs - Additional keyword arguments to forward on to `luci.builder`.
     """
 
@@ -423,6 +437,9 @@ def builder(
         fail('Setting "$build/code_coverage" property is not supported: ' +
              "use use_clang_coverage, use_java_coverage, coverage_exclude_sources" +
              " and/or coverage_test_types instead")
+    if "$recipe_engine/isolated" in properties:
+        fail('Setting "$recipe_engine/isolated" property is not supported: ' +
+             "use isolated_server instead")
     properties = dict(properties)
 
     os = defaults.get_value("os", os)
@@ -513,6 +530,12 @@ def builder(
     if code_coverage != None:
         properties["$build/code_coverage"] = code_coverage
 
+    isolated = _isolated_property(
+        isolated_server = isolated_server,
+    )
+    if isolated != None:
+        properties["$recipe_engine/isolated"] = isolated
+
     kwargs = dict(kwargs)
     if bucket != args.COMPUTE:
         kwargs["bucket"] = bucket