Support Using ScopedFeatureList in BrowserTest

base/test/test_suite.cc

Index: base/test/test_suite.cc
diff --git a/base/test/test_suite.cc b/base/test/test_suite.cc
index c9bfe9e0f0173558f90130aead0fabe5b8370864..ed0cedbca3ced030bef1be6bac9d96d4575eb804 100644
--- a/base/test/test_suite.cc
+++ b/base/test/test_suite.cc
@@ -342,13 +342,14 @@ void TestSuite::Initialize() {
     debug::WaitForDebugger(60, true);
   }
 #endif
-
   // Set up a FeatureList instance, so that code using that API will not hit a
   // an error that it's not set. If a FeatureList was created in this way (i.e.
   // one didn't exist previously), it will be cleared in Shutdown() via
   // ClearInstanceForTesting().
-  created_feature_list_ =
-      FeatureList::InitializeInstance(std::string(), std::string());
+  created_feature_list_ = FeatureList::InitializeInstance(

[Ilya Sherman, 2017/05/25 22:48:12]

Could you use a ScopedFeatureList here?

+      CommandLine::ForCurrentProcess()->GetSwitchValueASCII("enable-features"),
+      CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+          "disable-features"));

[Ilya Sherman, 2017/05/25 22:48:12]

It looks like the code expects that sometimes this InitializeInstance call might
fail.  That seems wrong.  Are there currently cases where it fails?  Can we
change the code to avoid the possibility of failure, and add an assertion to
that effect?

[Ilya Sherman, 2017/05/25 22:48:12]

nit: Please move the kEnabledFeatures and kDisabledFeatures constants into
//base, and use them here.

 
 #if defined(OS_IOS)
   InitIOSTestMessageLoop();