Force migrate all clients from multi-install back to single-install.

chrome/installer/mini_installer/chrome_appid.cc

Index: chrome/installer/mini_installer/chrome_appid.cc
diff --git a/chrome/installer/mini_installer/chrome_appid.cc b/chrome/installer/mini_installer/chrome_appid.cc
index 801cad82190b8de147958820c84bee43c5a0bd01..34d3134910cb24bac8ae4e834aa6946fa9abc5ce 100644
--- a/chrome/installer/mini_installer/chrome_appid.cc
+++ b/chrome/installer/mini_installer/chrome_appid.cc
@@ -5,8 +5,16 @@
 #include "chrome/installer/mini_installer/appid.h"
 
 namespace google_update {
+
+#if defined(GOOGLE_CHROME_BUILD)
 const wchar_t kAppGuid[] = L"{8A69D345-D564-463c-AFF1-A69D9E530F96}";
 const wchar_t kMultiInstallAppGuid[] =
     L"{4DC8B4CA-1BDA-483e-B5FA-D3C12E15B62D}";
 const wchar_t kSxSAppGuid[] = L"{4ea16ac7-fd5a-47c3-875b-dbf4a2008c20}";
-}
+#else
+const wchar_t kAppGuid[] = L"";
+const wchar_t kMultiInstallAppGuid[] = L"";
+const wchar_t kSxSAppGuid[] = L"";
+#endif
+
+}  // namespace google_update