MD History: Get sign in state from backend when refreshing the page

chrome/browser/ui/webui/history_login_handler.cc

Index: chrome/browser/ui/webui/history_login_handler.cc
diff --git a/chrome/browser/ui/webui/history_login_handler.cc b/chrome/browser/ui/webui/history_login_handler.cc
index c83c72f2abcd227ceb4bec79a3daa6805cfe6ddd..40dc37b631d3b05ce0c6bdee3b1c6e4239f856fe 100644
--- a/chrome/browser/ui/webui/history_login_handler.cc
+++ b/chrome/browser/ui/webui/history_login_handler.cc
@@ -23,6 +23,9 @@ void HistoryLoginHandler::RegisterMessages() {
   web_ui()->RegisterMessageCallback("otherDevicesInitialized",
       base::Bind(&HistoryLoginHandler::HandleOtherDevicesInitialized,
                  base::Unretained(this)));

[calamity, 2016/07/29 05:14:59]

Can we just reuse this message? It seems to be exactly the thing that solves
this problem in old history.

[lshang, 2016/07/29 06:11:58]

Done.

I thought it would be a little confusing to
chrome.send('otherDevicesInitialized') when the element is attached, but since
this is in synced tabs, it might make sense. I'm quite neutral on this, also
reuse this message will make this CL much simpler.

+  web_ui()->RegisterMessageCallback("getSignInState",
+      base::Bind(&HistoryLoginHandler::HandleGetSignInState,
+                 base::Unretained(this)));
 }
 
 void HistoryLoginHandler::HandleOtherDevicesInitialized(
@@ -30,6 +33,11 @@ void HistoryLoginHandler::HandleOtherDevicesInitialized(
   ProfileInfoChanged();
 }
 
+void HistoryLoginHandler::HandleGetSignInState(
+    const base::ListValue* /*args*/) {
+  ProfileInfoChanged();
+}
+
 void HistoryLoginHandler::ProfileInfoChanged() {
   bool signed_in = !profile_info_watcher_->GetAuthenticatedUsername().empty();
   web_ui()->CallJavascriptFunctionUnsafe("updateSignInState",