Add a promptBrowserLogin method to webstorePrivate extension API

Also change 'getSyncLogin' to 'getBrowserLogin', and add notion of the login
token to it (although this isn't actually sent yet).

BUG=58033
TEST=Should be covered by browser tests.


Review URL: http://codereview.chromium.org/3641001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@62172 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 603f6ecd..55ba15f 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -2750,6 +2750,7 @@
         'browser/sync/profile_sync_factory_impl.h',
         'browser/sync/profile_sync_service.cc',
         'browser/sync/profile_sync_service.h',
+        'browser/sync/profile_sync_service_observer.h',
         'browser/sync/signin_manager.cc',
         'browser/sync/signin_manager.h',
         'browser/sync/sync_constants.cc',