Avoid loading the chrome sign-in URLs in incognito

Chrome sign-in URLS are only supposed to be open in regular profiles and
loading them in incognito or guest profiles leads to crashes.

This CL avoids loading these URLs on incognito profiles.

Screenshots after this change in a guest session:
https://drive.google.com/a/chromium.org/file/d/0Bw1MJ8m7U5kbeHUxR0lZbGs4OFU/view?usp=sharing
https://drive.google.com/a/chromium.org/file/d/0Bw1MJ8m7U5kbV2I4TnJ4enpuazg/view?usp=sharing
https://drive.google.com/a/chromium.org/file/d/0Bw1MJ8m7U5kbLWdVOUZkc0JfeEU/view?usp=sharing

BUG=679265

Review-Url: https://codereview.chromium.org/2621083002
Cr-Commit-Position: refs/heads/master@{#443014}

chrome/browser/ui/webui/chrome_web_ui_controller_factory.cc

@@ -538,15 +538,19 @@ WebUIFactoryFunction GetWebUIFactoryFunction(WebUI* web_ui,
     return &NewWebUI<InspectUI>;
 #endif
 #if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
-  if (url.host_piece() == chrome::kChromeUIChromeSigninHost)
+  if (url.host_piece() == chrome::kChromeUIChromeSigninHost &&
+      !profile->IsOffTheRecord())
     return &NewWebUI<InlineLoginUI>;
   if (url.host_piece() == chrome::kChromeUIMdUserManagerHost)
     return &NewWebUI<MDUserManagerUI>;
-  if (url.host_piece() == chrome::kChromeUISigninErrorHost)
+  if (url.host_piece() == chrome::kChromeUISigninErrorHost &&
+      !profile->IsOffTheRecord())
     return &NewWebUI<SigninErrorUI>;
-  if (url.host_piece() == chrome::kChromeUISyncConfirmationHost)
+  if (url.host_piece() == chrome::kChromeUISyncConfirmationHost &&
+      !profile->IsOffTheRecord())
     return &NewWebUI<SyncConfirmationUI>;
-  if (url.host_piece() == chrome::kChromeUISigninEmailConfirmationHost)
+  if (url.host_piece() == chrome::kChromeUISigninEmailConfirmationHost &&
+      !profile->IsOffTheRecord())
     return &NewWebUI<SigninEmailConfirmationUI>;
   if (url.host_piece() == chrome::kChromeUIWelcomeHost)
     return &NewWebUI<WelcomeUI>;