Add remoting and PPAPI tests to GN build

remoting/remoting_test.gypi

Index: remoting/remoting_test.gypi
diff --git a/remoting/remoting_test.gypi b/remoting/remoting_test.gypi
index 7d3c50b9e458b871966041bd6b8b5c170e5fe182..b5db0a883967eebd4055b8ff6d865a7c9a78f4ce 100644
--- a/remoting/remoting_test.gypi
+++ b/remoting/remoting_test.gypi
@@ -5,6 +5,7 @@
 {
   'targets': [
     {
+      # GN version: //remoting:test_support
       'target_name': 'remoting_test_common',
       'type': 'static_library',
       'dependencies': [
@@ -20,6 +21,7 @@
         'remoting_resources',
       ],
       'sources': [
+        # Note: sources list duplicated in GN build.
         'host/fake_desktop_capturer.cc',
         'host/fake_desktop_capturer.h',
         'host/fake_desktop_environment.cc',
@@ -71,6 +73,9 @@
 
     # Remoting unit tests
     {
+      # GN version: //remoting:remoting_unittests
+      # Note that many of the sources are broken out into subdir-specific unit
+      # test source set targets that then GN version then brings together.
       'target_name': 'remoting_unittests',
       'type': '<(gtest_target_type)',
       'dependencies': [
@@ -107,6 +112,7 @@
         '../testing/gmock/include',
       ],
       'sources': [
+        # Note: sources list duplicated in GN build.
         'base/auth_token_util_unittest.cc',
         'base/auto_thread_task_runner_unittest.cc',
         'base/auto_thread_unittest.cc',