Convert Site Isolation Win bot to --isolate-extensions [2nd attempt].

testing/buildbot/filters/BUILD.gn

+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# This BUILD.gn file groups together filter files for particular test suites -
+# for example filters applicable to content_browsertests are exposed as
+# the //testing/buildbot/filters:content_browsertests target.
+
+# Note that all filter files (for a given test suite) are unconditionally listed
+# together, even if some filter files are applicable only to some platforms.
+# This should help avoid unpleasant surprises when a bot config is switched in
+# testing/buildbot/chromium.fyi.json without corresponding dependency changes
+# here - see https://crbug.com/661447.
+
+# To refresh, a command similar to the one below might be run in bash:
+# $ for i in $(ls -1 testing/buildbot/filters/*.browser_tests.*filter ); \
+#   do echo "    \"//$i\","; done | sort
+
+source_set("browser_tests") {
+  testonly = true
+
+  data = [
+    "//testing/buildbot/filters/browser-side-navigation.linux.browser_tests.filter",
+    "//testing/buildbot/filters/isolate-extensions.browser_tests.filter",
+    "//testing/buildbot/filters/mash.browser_tests.filter",
+    "//testing/buildbot/filters/mojo.fyi.browser_tests.filter",
+    "//testing/buildbot/filters/site-per-process.browser_tests.filter",
+  ]
+}
+
+source_set("content_browsertests") {

[jbudorick, 2016/11/09 18:20:44]

Can we rename these source sets? They prevent content_browsertests from being
identified as a single target because they share an unqualified name -- i.e., to
build content_browsertests, we now have to do

  ninja content/test:content_browsertests

+  testonly = true
+
+  data = [
+    "//testing/buildbot/filters/browser-side-navigation.linux.content_browsertests.filter",
+    "//testing/buildbot/filters/cast-linux.content_browsertests.filter",
+    "//testing/buildbot/filters/isolate-extensions.content_browsertests.filter",
+    "//testing/buildbot/filters/site-per-process.content_browsertests.filter",
+  ]
+}