Bug 775458 - Microsoft Security Essentials causes slow update fix. r=rstrong

browser/installer/windows/nsis/maintenanceservice_installer.nsi

@@ -190,11 +190,11 @@ Section "MaintenanceService"
   ${GetParameters} $0
   ${GetOptions} "$0" "/Upgrade" $0
   ${If} ${Errors}
-    nsExec::Exec '"$INSTDIR\$TempMaintServiceName" install'
+    ExecWait '"$INSTDIR\$TempMaintServiceName" install'
   ${Else}
     ; The upgrade cmdline is the same as install except
     ; It will fail if the service isn't already installed.
-    nsExec::Exec '"$INSTDIR\$TempMaintServiceName" upgrade'
+    ExecWait '"$INSTDIR\$TempMaintServiceName" upgrade'
   ${EndIf}
 
   WriteUninstaller "$INSTDIR\Uninstall.exe"
@@ -255,7 +255,7 @@ FunctionEnd
 
 Section "Uninstall"
   ; Delete the service so that no updates will be attempted
-  nsExec::Exec '"$INSTDIR\maintenanceservice.exe" uninstall'
+  ExecWait '"$INSTDIR\maintenanceservice.exe" uninstall'
 
   Push "$INSTDIR\updater.ini"
   Call un.RenameDelete

toolkit/components/maintenanceservice/maintenanceservice.cpp

@@ -15,6 +15,10 @@
 #include "uachelper.h"
 #include "updatehelper.h"
 
+// Link w/ subsystem window so we don't get a console when executing
+// this binary through the installer.
+#pragma comment(linker, "/SUBSYSTEM:windows")
+
 SERVICE_STATUS gSvcStatus = { 0 }; 
 SERVICE_STATUS_HANDLE gSvcStatusHandle = nullptr; 
 HANDLE gWorkDoneEvent = nullptr;