Support Using ScopedFeatureList in BrowserTest

base/command_line.h

Index: base/command_line.h
diff --git a/base/command_line.h b/base/command_line.h
index 3d29f8fee7fbb8de9e8c1fb691515ddb8bdccbdd..71243d1deffb16aa15d5a61f102dde97486d97ea 100644
--- a/base/command_line.h
+++ b/base/command_line.h
@@ -182,6 +182,8 @@ class BASE_EXPORT CommandLine {
                           const StringType& value);
   void AppendSwitchASCII(const std::string& switch_string,
                          const std::string& value);
+  void ReplaceSwitchASCIIForTesting(const std::string& switch_string,
+                                    const std::string& value);

[Ilya Sherman, 2017/05/25 22:48:11]

I happened to find this code [1] in a code search.  It looks like it's trying to
do approximately the same thing you're doing.  Can we unify the code paths?

[1]
https://cs.chromium.org/chromium/src/android_webview/browser/command_line_hel...

[chaopeng, 2017/05/26 00:57:41]

CommandLineHelper try to feature only if feature not in enable or disable list.
ScopedFeatureList want to override feature. But I want to change
CommandLineHelper to call ReplaceSwitchASCII.

 
   // Copy a set of switches (and any values) from another command line.
   // Commonly used when launching a subprocess.