Announce to Omaha that Chrome accepts CRX₂ and CRX₃ files.

components/update_client/update_query_params.cc

Index: components/update_client/update_query_params.cc
diff --git a/components/update_client/update_query_params.cc b/components/update_client/update_query_params.cc
index 5a81a94b775bf071503ca9ec977f50c8ebcb83d2..7b576e585b25c02ffd0c17b714f5283ca27ea971 100644
--- a/components/update_client/update_query_params.cc
+++ b/components/update_client/update_query_params.cc
@@ -71,8 +71,8 @@ UpdateQueryParamsDelegate* g_delegate = NULL;
 // static
 std::string UpdateQueryParams::Get(ProdId prod) {
   return base::StringPrintf(
-      "os=%s&arch=%s&nacl_arch=%s&prod=%s%s", kOs, kArch, GetNaclArch(),
-      GetProdIdString(prod),
+      "os=%s&arch=%s&nacl_arch=%s&prod=%s%s&acceptformat=crx2,crx3", kOs, kArch,
+      GetNaclArch(), GetProdIdString(prod),
       g_delegate ? g_delegate->GetExtraParams().c_str() : "");
 }