Add cloud_print_unittests to the GN build.

BUG=461019
R=brettw@chromium.org
CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:android_chromium_gn_compile_dbg,android_chromium_gn_compile_rel;tryserver.chromium.win:win8_chromium_gn_rel,win8_chromium_gn_dbg;tryserver.chromium.mac:mac_chromium_gn_rel,mac_chromium_gn_dbg

Review URL: https://codereview.chromium.org/1047463003

Cr-Original-Commit-Position: refs/heads/master@{#323262}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 9dfded663c2b6682c59ce5554c4d07564100ea5a

gn_migration.gypi

@@ -62,6 +62,7 @@
         '../chrome/chrome.gyp:sync_performance_tests',
         '../chrome/chrome.gyp:unit_tests',
         '../chrome/tools/profile_reset/jtl_compiler.gyp:jtl_compiler',
+        '../cloud_print/cloud_print.gyp:cloud_print_unittests',
         '../components/components.gyp:network_hints_browser',
         '../components/components.gyp:policy_templates',
         '../components/components.gyp:webui_generator',
@@ -436,7 +437,6 @@
       'conditions': [
         ['OS=="linux"', {
           'dependencies': [
-            '../cloud_print/cloud_print.gyp:cloud_print_unittests',
             '../third_party/webrtc/tools/tools.gyp:frame_analyzer',
             '../third_party/webrtc/tools/tools.gyp:rgba_to_i420_converter',