Introduce flag to disable static popular sites.

components/ntp_tiles/field_trial.cc

 // 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.
 
 #include "components/ntp_tiles/field_trial.h"
 
 #if defined(OS_ANDROID)
 #include <jni.h>
 #endif
 #include <string>
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
+#include "base/metrics/field_trial_params.h"
 #include "base/strings/string_util.h"
 #include "components/ntp_tiles/constants.h"
 #include "components/ntp_tiles/switches.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/jni_android.h"
 #include "jni/MostVisitedSites_jni.h"
 #endif
 
 namespace ntp_tiles {
@@ skipping 22 matching lines @@
   // On iOS, if not enrolled in the experiment, the default is to enable the
   // feature.
   if (group_name.empty())
     return true;
 #endif
 
   return base::StartsWith(group_name, "Enabled",
                           base::CompareCase::INSENSITIVE_ASCII);
 }
 
+bool ShouldUseBakedInSites() {
+  base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
+  if (cmd_line->HasSwitch(switches::kDisableNTPBakedInSites)) {
+    return false;
+  }
+
+  if (cmd_line->HasSwitch(switches::kEnableNTPBakedInSites)) {
+    return true;
+  }
+
+  const std::string& trial_value = base::GetFieldTrialParamValue(

[sfiera, 2017/03/16 10:15:40]

Three things:
* I think the "modern" thing to do is to associate params with a feature.
* If you do this, GetFieldTrialParamByFeatureAsBool() is an appropriate helper.
* Params can be set from the command line. Do you really need to read the
command line directly above?

[fhorschig, 2017/03/16 10:57:50]

Looks like an alternative approach. I don't need any params with a feature.
Changed it to use base::FeatureList::IsEnabled() as I don't need a
parameter anymore.
Dropped. Apparently, the same applies for features.

+      kPopularSitesFieldTrialName, kEnableBakedInSitesParamName);
+  // This feature is opt-out. Otherwise, users who need it would not get the
+  // right configuration timely enough. The configuration affects only Android
+  // or iOS users.
+  return trial_value.empty() || trial_value == "true";
+}
+
 }  // namespace ntp_tiles