mb: Add compile targets used by V8 trybot

testing/buildbot/gn_isolate_map.pyl

Index: testing/buildbot/gn_isolate_map.pyl
diff --git a/testing/buildbot/gn_isolate_map.pyl b/testing/buildbot/gn_isolate_map.pyl
index c33a56333ab835670691ea66d6cf5df5f19afb8a..89041b061ce85cb93094899f5ecc09b687be9d90 100644
--- a/testing/buildbot/gn_isolate_map.pyl
+++ b/testing/buildbot/gn_isolate_map.pyl
@@ -703,10 +703,18 @@
     "label": "//ui/ozone/gl:ozone_gl_unittests",
     "type": "console_test_launcher",
   },
+  "pdfium_test": {
+    "label": "//third_party/pdfium/samples:pdfium_test",
+    "type": "additional_compile_target",

[Michael Achenbach, 2016/09/19 12:44:40]

This is probably not just an additional compile target, but this should be
enough to unbreak our compile-only bot.

+  },
   "peerconnection_unittests": {
     "label": "//webrtc/api:peerconnection_unittests",
     "type": "console_test_launcher",
   },
+  "postmortem-metadata": {

[Michael Achenbach, 2016/09/19 12:44:40]

I'm wondering if some of these mappings should not live in the respective
subprojects?

+    "label": "//v8:postmortem-metadata",
+    "type": "additional_compile_target",
+  },
   "ppapi_unittests": {
     "label": "//ppapi:ppapi_unittests",
     "type": "console_test_launcher",