signin: force web signin flow initiated visits to accounts.google.com to their own process.

chrome/browser/ui/webui/sync_promo/sync_promo_ui.cc

Index: chrome/browser/ui/webui/sync_promo/sync_promo_ui.cc
diff --git a/chrome/browser/ui/webui/sync_promo/sync_promo_ui.cc b/chrome/browser/ui/webui/sync_promo/sync_promo_ui.cc
index 4c0920d235cedc0c7b9665202be3ad1614aaa0b5..de355cab3036751e14a630a4ee66d5a8a4b7a0da 100644
--- a/chrome/browser/ui/webui/sync_promo/sync_promo_ui.cc
+++ b/chrome/browser/ui/webui/sync_promo/sync_promo_ui.cc
@@ -259,6 +259,16 @@ GURL SyncPromoUI::GetSyncPromoURL(const GURL& next_page,
 }
 
 // static
+bool IsWebBasedSigninFlowURL(const GURL& url) {

[Roger Tawa OOO till Jul 10th, 2013/02/28 15:04:52]

Missing SyncPromoUI::, get unresolved external.

+  if (url.SchemeIs(chrome::kChromeSigninScheme))
+    return true;
+
+  return StartsWithASCII(url.spec(),
+                         GaiaUrls::GetInstance()->service_login_url(),
+                         false);

[Roger Tawa OOO till Jul 10th, 2013/02/28 04:07:42]

service_login_url() returns a URL that looks like https://a.g.c/ServiceLogin. 
If this is really what you want, then I think what you can compare the URL
ignoring any query parameters.  See
https://code.google.com/searchframe#OAMlx_jo-ck/src/chrome/browser/ui/sync/on...
for an example.

However, the chain of redirects during a sign in process could include something
else under https://a.g.c.  See
https://code.google.com/searchframe#OAMlx_jo-ck/src/chrome/browser/ui/sync/on...,
minus the checks for youtube and blogger.  I'll do some testing myself and see.

+}
+
+// static
 GURL SyncPromoUI::GetNextPageURLForSyncPromoURL(const GURL& url) {
   const char* key_name = UseWebBasedSigninFlow() ? kSyncPromoQueryKeyContinue :
       kSyncPromoQueryKeyNextPage;