[MD] Change appearance of incognito NTP to MD spec.

chrome/browser/ui/webui/theme_handler.cc

Index: chrome/browser/ui/webui/theme_handler.cc
diff --git a/chrome/browser/ui/webui/theme_handler.cc b/chrome/browser/ui/webui/theme_handler.cc
index 7759fa1d855379d49472d592a8ab53b3db31ad8e..f8b693cb3baac8f053a9c88aebaf0a8ec2384704 100644
--- a/chrome/browser/ui/webui/theme_handler.cc
+++ b/chrome/browser/ui/webui/theme_handler.cc
@@ -39,7 +39,11 @@ void ThemeHandler::Observe(int type,
                            const content::NotificationDetails& details) {
   DCHECK_EQ(chrome::NOTIFICATION_BROWSER_THEME_CHANGED, type);
   InitializeCSSCaches();
-  web_ui()->CallJavascriptFunction("ntp.themeChanged");
+  bool has_custom_bg = ThemeServiceFactory::GetForProfile(GetProfile())
+                           ->HasCustomImage(IDR_THEME_NTP_BACKGROUND);
+  base::DictionaryValue dictionary;
+  dictionary.SetBoolean("hasCustomBackground", has_custom_bg);
+  web_ui()->CallJavascriptFunction("ntp.themeChanged", dictionary);
 }
 
 void ThemeHandler::InitializeCSSCaches() {