Support Using ScopedFeatureList in BrowserTest

content/public/test/browser_test_base.cc

Index: content/public/test/browser_test_base.cc
diff --git a/content/public/test/browser_test_base.cc b/content/public/test/browser_test_base.cc
index d9e976e15f6bd23946a86a8676e7920e8c702cea..a3eb63c61783bf3ba9d58ff509544523d7c51368 100644
--- a/content/public/test/browser_test_base.cc
+++ b/content/public/test/browser_test_base.cc
@@ -240,11 +240,11 @@ void BrowserTestBase::SetUp() {
     base::FeatureList::GetInstance()->GetFeatureOverrides(&enabled_features,
                                                           &disabled_features);
   if (!enabled_features.empty())
-    command_line->AppendSwitchASCII(switches::kEnableFeatures,
-                                    enabled_features);
+    command_line->ReplaceSwitchASCIIForTest(switches::kEnableFeatures,
+                                            enabled_features);

[Ilya Sherman, 2017/05/16 06:43:32]

Hmm, shouldn't we extend the switch, rather than replacing it entirely?  That
is, if the switch already specifies some values, I thought we wanted to respect
those values (unless they were specifically overridden) -- no?

   if (!disabled_features.empty())
-    command_line->AppendSwitchASCII(switches::kDisableFeatures,
-                                    disabled_features);
+    command_line->ReplaceSwitchASCIIForTest(switches::kDisableFeatures,
+                                            disabled_features);
 
   // Need to wipe feature list clean, since BrowserMain calls
   // FeatureList::SetInstance, which expects no instance to exist.