Only allow installation of extensions/apps with gallery update url via download from gallery

chrome/common/extensions/extension_constants.cc

Index: chrome/common/extensions/extension_constants.cc
diff --git a/chrome/common/extensions/extension_constants.cc b/chrome/common/extensions/extension_constants.cc
index d0a64e1aa2307fa491fc4a2bbd3b1d3f71c33aca..cb1ae06734402f0458d71d0e33b6df902ca13063 100644
--- a/chrome/common/extensions/extension_constants.cc
+++ b/chrome/common/extensions/extension_constants.cc
@@ -256,6 +256,8 @@ namespace extension_urls {
 const char* kGalleryBrowsePrefix = "https://chrome.google.com/extensions";
 const char* kGalleryDownloadPrefix =
     "https://clients2.googleusercontent.com/crx/download";
+const char* kGalleryUpdateURL =
+    "http://clients2.google.com/service/update2/crx";
 const char* kMiniGalleryBrowsePrefix = "https://tools.google.com/chrome/";
 const char* kMiniGalleryDownloadPrefix = "https://dl-ssl.google.com/chrome/";
 }