Make the internal SimpleChrome builder compile 'chrome' and not 'all'.

Bug: 936957
Change-Id: Id6ab4c33c299aeecf03894124f1d15c2d95d7d4e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504257Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Ben Pastene <bpastene@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637865}

testing/buildbot/chromium.chrome.json

 {
   "AAAAA1 AUTOGENERATED FILE DO NOT EDIT": {},
-  "AAAAA2 See generate_buildbot_json.py to make changes": {}
+  "AAAAA2 See generate_buildbot_json.py to make changes": {},
+  "chromeos-amd64-generic-google-rel": {
+    "additional_compile_targets": [
+      "chrome"
+    ]
+  }
 }

testing/buildbot/generate_buildbot_json.py

@@ -933,6 +933,8 @@ class BBJSONGenerator(object):
       # chromium, due to https://crbug.com/878915
       'win-dbg',
       'win32-dbg',
+      # Defined in internal configs.
+      'chromeos-amd64-generic-google-rel',
     ]
 
   def check_input_file_consistency(self, verbose=False):

testing/buildbot/waterfalls.pyl

@@ -625,6 +625,11 @@
   {
     'name': 'chromium.chrome',
     'machines': {
+      'chromeos-amd64-generic-google-rel': {
+        'additional_compile_targets': [
+          'chrome',
+        ],
+      },
     },
   },
   {