[chrome://flags] Let features override params in the same trial

components/flags_ui/flags_state.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef COMPONENTS_FLAGS_UI_FLAGS_STATE_H_
 #define COMPONENTS_FLAGS_UI_FLAGS_STATE_H_
 
 #include <stddef.h>
 
 #include <map>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/command_line.h"
 #include "base/macros.h"
 
 namespace base {
 class FeatureList;
 class ListValue;
 }
 
 namespace flags_ui {
 
 // Internal functionality exposed for tests.
 namespace internal {
 // The trial group selected when feature variation parameters are registered via
 // FlagsState::RegisterFeatureVariationParameters().
-extern const char kTrialGroupAboutFlags[];
+extern const char kDefaultGroupNameAboutFlags[];
+// The trial name used when feature variation parameters are registered for a
+// FEATURE_WITH_VARIATIONS_VALUE_TYPE_WITH_DEFAULT_TRIAL FeatureEntry.
+extern const char kDefaultTrialNameAboutFlags[];
 }  // namespace internal
 
 struct FeatureEntry;
 class FlagsStorage;
 struct SwitchEntry;
 
 // Enumeration of OSs.
 enum {
   kOsMac = 1 << 0,
   kOsWin = 1 << 1,
@@ skipping 163 matching lines @@
   // Map from switch name to a set of string, that keeps track which strings
   // were appended to existing (list value) switches.
   std::map<std::string, std::set<std::string>> appended_switches_;
 
   DISALLOW_COPY_AND_ASSIGN(FlagsState);
 };
 
 }  // namespace flags_ui
 
 #endif  // COMPONENTS_FLAGS_UI_FLAGS_STATE_H_