Take 2 at browser_sync::ExtensionsActivityMonitor....

chrome/chrome.gyp

Index: chrome/chrome.gyp
===================================================================
--- chrome/chrome.gyp	(revision 30303)
+++ chrome/chrome.gyp	(working copy)
@@ -5210,6 +5210,8 @@
       'target_name': 'sync_unit_tests',
       'type': 'executable',
       'sources': [
+        'app/breakpad_mac_stubs.mm',
+        'app/keystone_glue.mm',
         'browser/sync/engine/all_status_unittest.cc',
         'browser/sync/engine/apply_updates_command_unittest.cc',
         'browser/sync/engine/auth_watcher_unittest.cc',
@@ -5224,6 +5226,7 @@
         'browser/sync/util/character_set_converters_unittest.cc',
         'browser/sync/util/crypto_helpers_unittest.cc',
         'browser/sync/util/event_sys_unittest.cc',
+        'browser/sync/util/extensions_activity_monitor_unittest.cc',
         'browser/sync/util/highres_timer_unittest.cc',
         'browser/sync/util/path_helpers_unittest.cc',
         'browser/sync/util/query_helpers_unittest.cc',
@@ -5247,12 +5250,14 @@
         '_USE_32BIT_TIME_T',
       ],
       'dependencies': [
-        '../testing/gtest.gyp:gtest',
-        '../third_party/libjingle/libjingle.gyp:libjingle',
-        'notifier',
-        'sync',
-        'sync_proto',
-        'test_support_unit',
+       'common',
+       'debugger',
+       '../skia/skia.gyp:skia',
+       '../testing/gtest.gyp:gtest',
+       '../third_party/libjingle/libjingle.gyp:libjingle',
+       'syncapi',
+       'sync_proto',
+       'test_support_unit',
       ],
       'conditions': [
         ['OS=="win"', {
@@ -5389,6 +5394,8 @@
         'browser/sync/util/dbgq.h',
         'browser/sync/util/event_sys-inl.h',
         'browser/sync/util/event_sys.h',
+        'browser/sync/util/extensions_activity_monitor.cc',
+        'browser/sync/util/extensions_activity_monitor.h',
         'browser/sync/util/fast_dump.h',
         'browser/sync/util/highres_timer.h',
         'browser/sync/util/highres_timer_linux.cc',
@@ -5421,6 +5428,7 @@
         '_USE_32BIT_TIME_T',
       ],
       'dependencies': [
+        '../skia/skia.gyp:skia',
         '../third_party/libjingle/libjingle.gyp:libjingle',
         'sync_proto',
       ],