Welcome page changes for Windows 10 and over.

chrome/browser/ui/startup/startup_browser_creator.h

Index: chrome/browser/ui/startup/startup_browser_creator.h
diff --git a/chrome/browser/ui/startup/startup_browser_creator.h b/chrome/browser/ui/startup/startup_browser_creator.h
index 0bec474e623a5752f6f73a771c5012f902ec0fe6..dad7bc97baa4237a6f8fe0b3eeb5e3ed7b17c225 100644
--- a/chrome/browser/ui/startup/startup_browser_creator.h
+++ b/chrome/browser/ui/startup/startup_browser_creator.h
@@ -19,6 +19,7 @@
 
 class Browser;
 class GURL;
+class PrefRegistrySimple;
 class PrefService;
 
 namespace base {
@@ -100,6 +101,10 @@ class StartupBrowserCreator {
   // For faking that no profiles have been launched yet.
   static void ClearLaunchedProfilesForTesting();
 
+#if defined(OS_WIN)

[msw, 2015/07/09 17:51:30]

Why not define this on all platforms and have an os-specific impl?

[grt (UTC plus 2), 2015/07/09 18:59:37]

No compelling reason. Done.

+  static void RegisterLocalStatePrefs(PrefRegistrySimple* registry);

[msw, 2015/07/09 17:51:30]

Why not add this to the impl class, where the prefs are used?

[grt (UTC plus 2), 2015/07/09 18:59:37]

Because I consider this .h to be the public facing portion of
browser/ui/startup. It seemed icky to me for code outside of here to care about
an implementation detail such as the impl class.

+#endif
+
  private:
   friend class CloudPrintProxyPolicyTest;
   friend class CloudPrintProxyPolicyStartupTest;