Allow whitelisted prefs to be displayed in ChromeOS in chrome://local-state.

chrome/browser/ui/webui/local_state/local_state_ui.cc

Index: chrome/browser/ui/webui/local_state/local_state_ui.cc
diff --git a/chrome/browser/ui/webui/local_state/local_state_ui.cc b/chrome/browser/ui/webui/local_state/local_state_ui.cc
index 22740b170aed2da1de510627ecdb5e800432cc78..1a5f411f77ff85075e446ff2f4a958dbba0e60d2 100644
--- a/chrome/browser/ui/webui/local_state/local_state_ui.cc
+++ b/chrome/browser/ui/webui/local_state/local_state_ui.cc
@@ -13,6 +13,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/url_constants.h"
 #include "components/prefs/pref_service.h"
+#include "components/variations/pref_names.h"
 #include "content/public/browser/web_ui.h"
 #include "content/public/browser/web_ui_controller.h"
 #include "content/public/browser/web_ui_data_source.h"
@@ -51,10 +52,16 @@ void LocalStateUIHandler::RegisterMessages() {
 }
 
 void LocalStateUIHandler::HandleRequestJson(const base::ListValue* args) {
-#if !defined(OS_CHROMEOS)
+#if defined(OS_CHROMEOS)
+  std::vector<std::string> whitelisted_prefixes = {
+      "variations", "user_experience_metrics", "uninstall_metrics"};
+  std::unique_ptr<base::DictionaryValue> local_state_values(
+      g_browser_process->local_state()
+          ->GetWhitelistedPreferenceValuesOmitDefaults(whitelisted_prefixes));

[Bernhard Bauer, 2016/04/22 18:24:38]

Couldn't we just do the whitelisting here? We would end up making a couple of
unnecessary copies of the values outside of the whitelist, but it's just for a
debugging page, and we wouldn't be blocking the UI thread for longer than we
would for full GetPreferenceValuesOmitDefaults() anyway.

[hamelphi, 2016/04/22 20:31:28]

I was on the fence between doing the filtering here or in pref_service. I don't
feel strongly one way or another. I moved the filtering here instead.

+#else
   std::unique_ptr<base::DictionaryValue> local_state_values(
       g_browser_process->local_state()->GetPreferenceValuesOmitDefaults());
-
+#endif  // !defined(OS_CHROMEOS)
   std::string json;
   JSONStringValueSerializer serializer(&json);
   serializer.set_pretty_print(true);
@@ -64,7 +71,6 @@ void LocalStateUIHandler::HandleRequestJson(const base::ListValue* args) {
 
   web_ui()->CallJavascriptFunction("localState.setLocalState",
                                    base::StringValue(json));
-#endif  // !defined(OS_CHROMEOS)
 }
 
 }  // namespace