Change ScopedFeatureList to overrides FeatureList not reset

base/test/scoped_feature_list.h

 // Copyright 2016 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 BASE_TEST_SCOPED_FEATURE_LIST_H_
 #define BASE_TEST_SCOPED_FEATURE_LIST_H_
 
 #include <initializer_list>
 
 #include "base/feature_list.h"
@@ skipping 10 matching lines @@
  public:
   ScopedFeatureList();
   ~ScopedFeatureList();
 
   // Initializes and registers a FeatureList instance with no overrides.
   void Init();
 
   // Initializes and registers the given FeatureList instance.
   void InitWithFeatureList(std::unique_ptr<FeatureList> feature_list);
 
-  // Initializes and registers a FeatureList instance with the given enabled
-  // and disabled features.
+  // Initializes and registers a FeatureList instance with only the given
+  // enabled and disabled features (comma-separated names).

[Ilya Sherman, 2017/04/21 22:43:34]

For this function and the two above it, please add a warning that these should
be used only in very rare cases.  Something like:

  // WARNING: This method will reset any globally configured features to their
  // default values, which can hide feature interaction bugs. Please use
  // sparingly.  https://crbug.com/NNNNNN

+  void InitFromCommandLine(const std::string& enable_features,
+                           const std::string& disable_features);
+
+  // Initializes and registers a FeatureList instance overrided with the given

[Ilya Sherman, 2017/04/21 22:43:34]

nit: s/overrided/overridden (applies throughout)

+  // enabled and disabled features.

[Ilya Sherman, 2017/04/21 22:43:34]

nit: To add a bit of clarity here, please add a bit more descriptive text, along
the lines of

  // Any feature overrides already present in the global FeatureList will
  // continue to apply, unless they conflict with the overrides passed into this
  // method. This is important for testing potentially unexpected feature
  // interactions.

(I think it's fine to only go into this extra detail for this method, and leave
the simpler docs for the two methods below.)

   void InitWithFeatures(
       const std::initializer_list<base::Feature>& enabled_features,
       const std::initializer_list<base::Feature>& disabled_features);
 
-  // Initializes and registers a FeatureList instance with the given
-  // enabled and disabled features (comma-separated names).
-  void InitFromCommandLine(const std::string& enable_features,
-                           const std::string& disable_features);
-
-  // Initializes and registers a FeatureList instance enabling a single
-  // feature.
+  // Initializes and registers a FeatureList instance overrided with single
+  // enabled feature.
   void InitAndEnableFeature(const base::Feature& feature);
 
-  // Initializes and registers a FeatureList instance disabling a single
-  // feature.
+  // Initializes and registers a FeatureList instance overrided with single
+  // disabled feature.
   void InitAndDisableFeature(const base::Feature& feature);
 
  private:
   std::unique_ptr<FeatureList> original_feature_list_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedFeatureList);
 };
 
 }  // namespace test
 }  // namespace base
 
 #endif  // BASE_TEST_SCOPED_FEATURE_LIST_H_