Fix perfbotnot feature param setting from trial testing config.

tools/variations/fieldtrial_util.py

Index: tools/variations/fieldtrial_util.py
diff --git a/tools/variations/fieldtrial_util.py b/tools/variations/fieldtrial_util.py
index 024894ab21ea7f219151282a1878adbdcc5e158a..bc21d69d782dd69c6e9fa8c48f028fc4eae56735 100644
--- a/tools/variations/fieldtrial_util.py
+++ b/tools/variations/fieldtrial_util.py
@@ -32,14 +32,18 @@ def _FindDuplicates(entries):
   return duplicates
 
 def _CheckForDuplicateFeatures(enable_features, disable_features):
+  enable_features = [f.split('<')[0] for f in enable_features]
   enable_features_set = set(enable_features)
   if len(enable_features_set) != len(enable_features):
     raise Exception('Duplicate feature(s) in enable_features: ' +
                     ', '.join(_FindDuplicates(enable_features)))
+
+  disable_features = [f.split('<')[0] for f in disable_features]
   disable_features_set = set(disable_features)
   if len(disable_features_set) != len(disable_features):
     raise Exception('Duplicate feature(s) in disable_features: ' +
                     ', '.join(_FindDuplicates(disable_features)))
+
   features_in_both = enable_features_set.intersection(disable_features_set)
   if len(features_in_both) > 0:
     raise Exception('Conflicting features set as both enabled and disabled: ' +
@@ -79,10 +83,10 @@ def GenerateArgs(config_path, platform):
        param_list = [_escape(x) for x in param_list]
        param = '%s:%s' % ('.'.join(selected_study), '/'.join(param_list))
        params.append(param)
-    if 'enable_features' in experiment:
-      enable_features.extend(experiment['enable_features'])
-    if 'disable_features' in experiment:
-      disable_features.extend(experiment['disable_features'])
+    for feature in experiment.get('enable_features', []):
+      enable_features.append(feature + '<' + study_name)
+    for feature in experiment.get('disable_features', []):
+      disable_features.append(feature + '<' + study_name)
 
   if not len(studies):
     return []
@@ -91,9 +95,9 @@ def GenerateArgs(config_path, platform):
   if len(params):
     args.append('--force-fieldtrial-params=%s' % ','.join(params))
   if len(enable_features):
-    args.append('--enable-features=%s' % ','.join(enable_features))
+    args.append('--enable-features="%s"' % ','.join(enable_features))
   if len(disable_features):
-    args.append('--disable-features=%s' % ','.join(disable_features))
+    args.append('--disable-features="%s"' % ','.join(disable_features))
   return args
 
 def main():