Support Using ScopedFeatureList in BrowserTest

content/public/test/browser_test_base.cc

 // Copyright (c) 2011 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.
 
 #include "content/public/test/browser_test_base.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 212 matching lines @@
 
   if (use_software_gl && !use_software_compositing_)
     command_line->AppendSwitch(switches::kOverrideUseSoftwareGLForTests);
 
   test_host_resolver_ = base::MakeUnique<TestHostResolver>();
 
   ContentBrowserSanityChecker scoped_enable_sanity_checks;
 
   SetUpInProcessBrowserTestFixture();
 
+  DCHECK(!command_line->HasSwitch(switches::kEnableFeatures))
+      << "Should not use CommandLine to modify features.";

[Ilya Sherman, 2017/06/13 22:42:48]

Please list this as a comment if you'd like to include it.  Outputting strings
with DCHECKs adds weight to the binary, and hence is only recommended when
outputting non-static data, e.g. a filename.

[chaopeng, 2017/06/28 14:16:51]

Done.

+  DCHECK(!command_line->HasSwitch(switches::kDisableFeatures))
+      << "Should not use CommandLine to modify features.";
+
   // At this point, copy features to the command line, since BrowserMain will
   // wipe out the current feature list.
   std::string enabled_features;
   std::string disabled_features;
   if (base::FeatureList::GetInstance()) {
     base::FeatureList::GetInstance()->GetFeatureOverrides(&enabled_features,
                                                           &disabled_features);
   }
   if (!enabled_features.empty()) {
     command_line->AppendSwitchASCII(switches::kEnableFeatures,
@@ skipping 164 matching lines @@
     return;
 
   mojom::NetworkServiceTestPtr network_service_test;
   ServiceManagerConnection::GetForProcess()->GetConnector()->BindInterface(
       mojom::kNetworkServiceName, &network_service_test);
   mojo::SyncCallRestrictions::ScopedAllowSyncCall allow_sync_call;
   network_service_test->AddRules(std::move(mojo_rules));
 }
 
 }  // namespace content