Let CrWinClang64(dbg) use gn.

scripts/slave/recipes/chromium.expected/full_chromium_fyi_CrWinClang64_dbg_.json

Index: scripts/slave/recipes/chromium.expected/full_chromium_fyi_CrWinClang64_dbg_.json
===================================================================
--- scripts/slave/recipes/chromium.expected/full_chromium_fyi_CrWinClang64_dbg_.json	(revision 295571)
+++ scripts/slave/recipes/chromium.expected/full_chromium_fyi_CrWinClang64_dbg_.json	(working copy)
@@ -74,28 +74,34 @@
     "cmd": [
       "python",
       "-u",
-      "[SLAVE_BUILD]\\src\\tools\\swarming_client\\swarming.py",
-      "--version"
+      "[DEPOT_TOOLS]\\gclient.py",
+      "runhooks"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "name": "swarming.py --version",
-    "stdout": "/path/to/tmp/",
-    "~followup_annotations": [
-      "@@@STEP_TEXT@0.4.10@@@"
-    ]
+    "env": {
+      "GYP_CHROMIUM_NO_ACTION": "1"
+    },
+    "name": "gclient runhooks"
   },
   {
     "cmd": [
       "python",
       "-u",
-      "[DEPOT_TOOLS]\\gclient.py",
-      "runhooks"
+      "[SLAVE_BUILD]\\src\\tools\\mb\\mb.py",
+      "gen",
+      "-v",
+      "-m",
+      "chromium.fyi",
+      "-b",
+      "CrWinClang64(dbg)",
+      "--config-file",
+      "[SLAVE_BUILD]\\src\\tools\\mb\\mb_config.pyl",
+      "--goma-dir",
+      "[BUILD]\\goma",
+      "//out/Debug_x64"
     ],
     "cwd": "[SLAVE_BUILD]",
-    "env": {
-      "GYP_DEFINES": "clang=1 component=shared_library fastbuild=1 target_arch=x64 test_isolation_mode=prepare"
-    },
-    "name": "gclient runhooks"
+    "name": "generate_build_files"
   },
   {
     "cmd": [
@@ -109,18 +115,7 @@
     "name": "read test spec",
     "~followup_annotations": [
       "@@@STEP_TEXT@path: [SLAVE_BUILD]\\src\\testing\\buildbot\\chromium.fyi.json@@@",
-      "@@@STEP_LOG_LINE@json.output@{@@@",
-      "@@@STEP_LOG_LINE@json.output@  \"CrWinClang64(dbg) tester\": {@@@",
-      "@@@STEP_LOG_LINE@json.output@    \"gtest_tests\": [@@@",
-      "@@@STEP_LOG_LINE@json.output@      {@@@",
-      "@@@STEP_LOG_LINE@json.output@        \"swarming\": {@@@",
-      "@@@STEP_LOG_LINE@json.output@          \"can_use_on_swarming_builders\": true@@@",
-      "@@@STEP_LOG_LINE@json.output@        }, @@@",
-      "@@@STEP_LOG_LINE@json.output@        \"test\": \"browser_tests\"@@@",
-      "@@@STEP_LOG_LINE@json.output@      }@@@",
-      "@@@STEP_LOG_LINE@json.output@    ]@@@",
-      "@@@STEP_LOG_LINE@json.output@  }@@@",
-      "@@@STEP_LOG_LINE@json.output@}@@@",
+      "@@@STEP_LOG_LINE@json.output@{}@@@",
       "@@@STEP_LOG_END@json.output@@@"
     ]
   },
@@ -156,18 +151,6 @@
     "name": "cleanup_temp"
   },
   {
-    "cmd": [
-      "python",
-      "-u",
-      "RECIPE_MODULE[isolate]\\resources\\find_isolated_tests.py",
-      "--build-dir",
-      "[SLAVE_BUILD]\\src\\out\\Debug_x64",
-      "--clean-isolated-files"
-    ],
-    "cwd": "[SLAVE_BUILD]",
-    "name": "clean isolated files"
-  },
-  {
     "allow_subannotations": true,
     "cmd": [
       "python",
@@ -206,42 +189,6 @@
     "name": "compile"
   },
   {
-    "cmd": [
-      "python",
-      "-u",
-      "RECIPE_MODULE[isolate]\\resources\\remove_build_metadata.py",
-      "--build-dir",
-      "[SLAVE_BUILD]\\src\\out\\Debug_x64",
-      "--src-dir",
-      "[SLAVE_BUILD]\\src"
-    ],
-    "cwd": "[SLAVE_BUILD]",
-    "name": "remove_build_metadata"
-  },
-  {
-    "cmd": [
-      "python",
-      "-u",
-      "RECIPE_MODULE[isolate]\\resources\\isolate.py",
-      "[SLAVE_BUILD]\\src\\tools\\swarming_client",
-      "batcharchive",
-      "--dump-json",
-      "/path/to/tmp/json",
-      "--isolate-server",
-      "https://isolateserver.appspot.com",
-      "--verbose",
-      "[SLAVE_BUILD]\\src\\out\\Debug_x64\\browser_tests.isolated.gen.json"
-    ],
-    "cwd": "[SLAVE_BUILD]",
-    "name": "isolate tests",
-    "~followup_annotations": [
-      "@@@STEP_LOG_LINE@json.output@{@@@",
-      "@@@STEP_LOG_LINE@json.output@  \"browser_tests\": \"[dummy hash for browser_tests]\"@@@",
-      "@@@STEP_LOG_LINE@json.output@}@@@",
-      "@@@STEP_LOG_END@json.output@@@"
-    ]
-  },
-  {
     "allow_subannotations": true,
     "cmd": [
       "python",