Add reset all button to flags page

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index f0ade212558075a897dd75445079875d2d3e9953..10a739a15fb343b6f6ca42bfba34f4b8dbea2f7b 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1293,6 +1293,7 @@ class FlagsState {
       PrefService* prefs, const std::string& internal_name, bool enable);
   void RemoveFlagsSwitches(
       std::map<std::string, CommandLine::StringType>* switch_list);
+  void ResetAllFlags(PrefService* prefs);
   void reset();
 
   // Returns the singleton instance of this class
@@ -1514,6 +1515,10 @@ void RemoveFlagsSwitches(
   FlagsState::GetInstance()->RemoveFlagsSwitches(switch_list);
 }
 
+void ResetAllFlags(PrefService* prefs) {
+  FlagsState::GetInstance()->ResetAllFlags(prefs);
+}
+
 int GetCurrentPlatform() {
 #if defined(OS_MACOSX)
   return kOsMac;
@@ -1679,6 +1684,13 @@ void FlagsState::RemoveFlagsSwitches(
   }
 }
 
+void FlagsState::ResetAllFlags(PrefService* prefs) {
+  needs_restart_ = true;
+
+  std::set<std::string> no_experiments;
+  SetEnabledFlags(prefs, no_experiments);
+}
+
 void FlagsState::reset() {
   needs_restart_ = false;
   flags_switches_.clear();