Update AutoImport to import nothing by default (in absence of policy and master_prefs).

chrome/browser/ui/browser_ui_prefs.cc

Index: chrome/browser/ui/browser_ui_prefs.cc
diff --git a/chrome/browser/ui/browser_ui_prefs.cc b/chrome/browser/ui/browser_ui_prefs.cc
index c01a8466a080e60264af93080a12b5dadba77b2f..dcaf9764904d063825a71126c16e9326dcccfb63 100644
--- a/chrome/browser/ui/browser_ui_prefs.cc
+++ b/chrome/browser/ui/browser_ui_prefs.cc
@@ -71,12 +71,12 @@ void RegisterBrowserUserPrefs(user_prefs::PrefRegistrySyncable* registry) {
   registry->RegisterDictionaryPref(prefs::kBrowserWindowPlacement);
   registry->RegisterDictionaryPref(prefs::kBrowserWindowPlacementPopup);
   registry->RegisterDictionaryPref(prefs::kAppWindowPlacement);
-  registry->RegisterBooleanPref(prefs::kImportAutofillFormData, true);
-  registry->RegisterBooleanPref(prefs::kImportBookmarks, true);
-  registry->RegisterBooleanPref(prefs::kImportHistory, true);
-  registry->RegisterBooleanPref(prefs::kImportHomepage, true);
-  registry->RegisterBooleanPref(prefs::kImportSavedPasswords, true);
-  registry->RegisterBooleanPref(prefs::kImportSearchEngine, true);
+  registry->RegisterBooleanPref(prefs::kImportAutofillFormData, false);

[grt (UTC plus 2), 2017/02/23 14:05:48]

this will cause all checkboxes in chrome://settings/importData to be unchecked
by default, no? i don't think this is the right thing.

[gab, 2017/02/23 20:37:40]

Right, I'd seen those and initially thought it made sense for them to reflect
what was imported on first run but you now make me realize that having these all
unchecked by default is not great.

Also, I thought it was merely reading the value without setting it back but now
I realize I just happen to know nothing about webUI: it's actually hooked up to
the pref (and toggles the actual pref live when using the UI) :
https://cs.chromium.org/search/?q=(%22%7C%27)import_history(%22%7C%27)&sq=pac...
(I think the import_data_overlay.html bit is the critical hook).

Thinking about this some more, I don't think it makes sense for this UI to be
driven by policies for the same pref as auto import... I don't even know that it
makes sense for it to be driven by policies at all? That would mean that a
policy could prevent import even if the user explicitly wants to tick that box?

+ewald, can you look into this?

+  registry->RegisterBooleanPref(prefs::kImportBookmarks, false);
+  registry->RegisterBooleanPref(prefs::kImportHistory, false);
+  registry->RegisterBooleanPref(prefs::kImportHomepage, false);
+  registry->RegisterBooleanPref(prefs::kImportSavedPasswords, false);
+  registry->RegisterBooleanPref(prefs::kImportSearchEngine, false);
   registry->RegisterBooleanPref(
       prefs::kEnableDoNotTrack,
       false,