Allow Signin page to open other chrome:// URLs if login content in <webview>

chrome/browser/chrome_content_browser_client.cc

Index: chrome/browser/chrome_content_browser_client.cc
diff --git a/chrome/browser/chrome_content_browser_client.cc b/chrome/browser/chrome_content_browser_client.cc
index cf63aa7cf1ec233a8427de64bbba0c5e8ce9d4c0..0c15c4634cae01e2ea326529239a6b5c5523d6b1 100644
--- a/chrome/browser/chrome_content_browser_client.cc
+++ b/chrome/browser/chrome_content_browser_client.cc
@@ -1053,8 +1053,11 @@ bool ChromeContentBrowserClient::ShouldAllowOpenURL(
 #endif
 
   // Do not allow chrome://chrome-signin navigate to other chrome:// URLs, since
-  // the signin page may host untrusted web content.
-  if (from_url.GetOrigin().spec() == chrome::kChromeUIChromeSigninURL &&
+  // the signin page may host untrusted web content when <webview>-based signin
+  // is not enabled. In the <webview> case, untrusted content is out-of-process
+  // and cannot navigate to chrome:// URLs.
+  if (!switches::IsEnableWebviewBasedSignin() &&

[Charlie Reis, 2015/02/04 22:02:57]

I'm still hesitant to change this.  It sounds like it's not necessary for fixing
the bug (since Language Settings will go straight to OpenURLFromTab and not
through here), while inline_login.js continues to route any newwindow events
from the webview (if any) through here.

Why do we need to skip the check?  And do we still need onNewWindow in
inline_login.js?

+      from_url.GetOrigin().spec() == chrome::kChromeUIChromeSigninURL &&
       url.SchemeIs(content::kChromeUIScheme) &&
       url.host() != chrome::kChromeUIChromeSigninHost) {
     VLOG(1) << "Blocked navigation to " << url.spec() << " from "