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..3c57261980ee6ec3ffab44ebacf70b1a7beb58d5 100644
--- a/chrome/browser/ui/webui/local_state/local_state_ui.cc
+++ b/chrome/browser/ui/webui/local_state/local_state_ui.cc
@@ -4,8 +4,6 @@
 
 #include "chrome/browser/ui/webui/local_state/local_state_ui.h"
 
-#include <string>
-
 #include "base/json/json_string_value_serializer.h"
 #include "base/macros.h"
 #include "build/build_config.h"
@@ -19,8 +17,43 @@
 #include "content/public/browser/web_ui_message_handler.h"
 #include "grit/browser_resources.h"
 
+namespace internal {

[Alexei Svitkine (slow), 2016/04/25 21:30:13]

Move the internal namespace below the anon namespace. Then, HasValidPrefix() can
be in the normal anon namespace.

[hamelphi, 2016/04/26 15:25:28]

Done.

+
+namespace {

[Alexei Svitkine (slow), 2016/04/25 21:30:13]

Nit: Add an empty line below this above above the closing.

[hamelphi, 2016/04/26 15:25:28]

Done.

+bool HasValidPrefix(const std::string& pref_name,

[Alexei Svitkine (slow), 2016/04/25 21:30:13]

Nit: Add a short comment above this function.

[hamelphi, 2016/04/26 15:25:28]

Done.

+                    const std::vector<std::string> valid_prefixes) {
+  for (const std::string& prefix : valid_prefixes) {
+    if (pref_name.compare(0, prefix.size(), prefix) == 0)
+      return true;
+  }
+  return false;
+}
+}  // namespace
+
+void FilterPrefs(const std::vector<std::string>& valid_prefixes,
+                 base::DictionaryValue* prefs) {
+  std::vector<std::string> prefs_to_remove;
+  for (base::DictionaryValue::Iterator it(*prefs); !it.IsAtEnd();
+       it.Advance()) {
+    if (!HasValidPrefix(it.key(), valid_prefixes))
+      prefs_to_remove.push_back(it.key());
+  }
+  for (const std::string& pref_to_remove : prefs_to_remove) {
+    std::unique_ptr<base::Value> removed_value;
+    bool successfully_removed = prefs->Remove(pref_to_remove, &removed_value);
+    DCHECK(successfully_removed);
+  }
+}
+}  // namespace internal
+
 namespace {
 
+#if defined(OS_CHROMEOS)
+#define ENABLE_FILTERING true
+#else
+#define ENABLE_FILTERING false
+#endif  // defined(OS_CHROMEOS)
+
 // UI Handler for chrome://local-state. Displays the Local State file as JSON.
 class LocalStateUIHandler : public content::WebUIMessageHandler {
  public:
@@ -51,10 +84,13 @@ void LocalStateUIHandler::RegisterMessages() {
 }
 
 void LocalStateUIHandler::HandleRequestJson(const base::ListValue* args) {
-#if !defined(OS_CHROMEOS)
   std::unique_ptr<base::DictionaryValue> local_state_values(
       g_browser_process->local_state()->GetPreferenceValuesOmitDefaults());
-
+  if (ENABLE_FILTERING) {
+    std::vector<std::string> whitelisted_prefixes = {
+        "variations", "user_experience_metrics", "uninstall_metrics"};
+    internal::FilterPrefs(whitelisted_prefixes, local_state_values.get());
+  }
   std::string json;
   JSONStringValueSerializer serializer(&json);
   serializer.set_pretty_print(true);
@@ -64,7 +100,6 @@ void LocalStateUIHandler::HandleRequestJson(const base::ListValue* args) {
 
   web_ui()->CallJavascriptFunction("localState.setLocalState",
                                    base::StringValue(json));
-#endif  // !defined(OS_CHROMEOS)
 }
 
 }  // namespace