Add END event for StartSandboxedProcess.

BUG=None
TEST=Go to chrome://tracing, select only 'ETW Event Trace' catagory and start a new tab.  Stop tracing, and check that StartProcessWithAccess does not say "Did Not Finish".

Review URL: https://codereview.chromium.org/388513002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@282811 0039d316-1c4b-4281-b951-d872f2087c98

content/common/sandbox_win.cc

@@ -739,6 +739,7 @@ base::ProcessHandle StartSandboxedProcess(
     delegate->PostSpawnTarget(target.process_handle());
 
   ResumeThread(target.thread_handle());
+  TRACE_EVENT_END_ETW("StartProcessWithAccess", 0, type_str);
   return target.TakeProcessHandle();
 }