[devtools] Configure devtools-specific builder

We'll limit testing on the new builder to devtools-specific tests in a follow up CL.

Bug: 1018204
Change-Id: I45e7442258f4de47999fc1d0b26cd1b31b96e5ca
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1899502
Auto-Submit: Liviu Rau <liviurau@chromium.org>
Commit-Queue: Liviu Rau <liviurau@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#714531}

testing/buildbot/generate_buildbot_json.py

@@ -1096,7 +1096,9 @@ class BBJSONGenerator(object):
             # These waterfalls have their bot configs in a different repo.
             # so we don't know about their bot names.
             continue  # pragma: no cover
-          if waterfall['name'] in ['client.devtools-frontend.integration']:
+          if waterfall['name'] in [
+              'client.devtools-frontend.integration',
+              'tryserver.devtools-frontend']:
             continue  # pragma: no cover
           raise self.unknown_bot(bot_name, waterfall['name'])
 

testing/buildbot/tryserver.devtools-frontend.json

+{
+  "AAAAA1 AUTOGENERATED FILE DO NOT EDIT": {},
+  "AAAAA2 See generate_buildbot_json.py to make changes": {},
+  "devtools_frontend_linux_blink_light_rel": {
+    "isolated_scripts": [
+      {
+        "args": [
+          "--num-retries=3"
+        ],
+        "isolate_name": "blink_web_tests_exparchive",
+        "merge": {
+          "args": [
+            "--verbose"
+          ],
+          "script": "//third_party/blink/tools/merge_web_test_results.py"
+        },
+        "name": "webkit_layout_tests",
+        "results_handler": "layout tests",
+        "swarming": {
+          "can_use_on_swarming_builders": true,
+          "dimension_sets": [
+            {
+              "os": "Ubuntu-16.04"
+            }
+          ],
+          "shards": 12
+        }
+      }
+    ]
+  }
+}

testing/buildbot/waterfalls.pyl

@@ -4462,6 +4462,19 @@
       },
     },
   },
+  {
+    'name': 'tryserver.devtools-frontend',
+    'machines': {
+      'devtools_frontend_linux_blink_light_rel': {
+        'mixins': [
+          'linux-xenial',
+        ],
+        'test_suites': {
+          'isolated_scripts': 'chromium_webkit_isolated_scripts',
+        },
+      },
+    }
+  },
   {
     'name': 'tryserver.webrtc',
     'machines': {