Undo the startup_helper_win.h change in r143501 because that breaks the sandbox in component builds.

chrome/chrome_tests.gypi

Index: chrome/chrome_tests.gypi
===================================================================
--- chrome/chrome_tests.gypi	(revision 143501)
+++ chrome/chrome_tests.gypi	(working copy)
@@ -513,6 +513,7 @@
         'test/base/chrome_test_launcher.cc',
         'test/base/view_event_test_base.cc',
         'test/base/view_event_test_base.h',
+        '../content/app/startup_helper_win.cc',
         '../content/browser/mouseleave_browsertest.cc',
       ],
       'conditions': [
@@ -3000,6 +3001,7 @@
         # TODO(craig): Rename this and run from base_unittests when the test
         # is safe to run there. See http://crbug.com/78722 for details.
         '../base/files/file_path_watcher_browsertest.cc',
+        '../content/app/startup_helper_win.cc',
         '../content/browser/accessibility/cross_platform_accessibility_browsertest.cc',
         '../content/browser/accessibility/dump_accessibility_tree_browsertest.cc',
         '../content/browser/accessibility/dump_accessibility_tree_helper.cc',
@@ -3418,6 +3420,7 @@
         'test/perf/browser_perf_test.h',
         'test/perf/rendering/latency_tests.cc',
         'test/perf/rendering/throughput_tests.cc',
+        '../content/app/startup_helper_win.cc',
       ],
       'rules': [
         {
@@ -3563,6 +3566,7 @@
         'app/chrome_dll.rc',
         'browser/safe_browsing/safe_browsing_test.cc',
         'test/base/chrome_test_launcher.cc',
+        '../content/app/startup_helper_win.cc',
       ],
       'conditions': [
         ['safe_browsing==0', {
@@ -3926,6 +3930,7 @@
         'browser/sync/test/integration/two_client_typed_urls_sync_test.cc',
         'browser/sync/test/integration/typed_urls_helper.cc',
         'browser/sync/test/integration/typed_urls_helper.h',
+        '../content/app/startup_helper_win.cc',
       ],
       'conditions': [
         ['toolkit_uses_gtk == 1', {
@@ -4048,6 +4053,7 @@
         'browser/sync/test/integration/typed_urls_helper.h',
         'test/base/chrome_test_launcher.cc',
         'test/data/resource.rc',
+        '../content/app/startup_helper_win.cc',
       ],
       'conditions': [
         ['toolkit_uses_gtk == 1', {