Fix perfbotnot feature param setting from trial testing config.

Previously, params that were queried via their associated features
would not get correctly picked by perfbots using the field trial
testing config.

This was caused by the generated command-line not using the
--enable-features=FeatureName<TrialName syntax. This syntax is
needed in order to estable the link between a feature and its
associated trial, so that when a field-trial param is looked up
by feature, it's able to find it from the associated trial.

Adds quotations to these params since "<" characters would
otherwise get interpreted by some shells.

PERF SHERIFFS: This CL may cause perf bots to move - if so, it
means that one of the entries in the field trial testing config
that uses both params and features is causing the change but was
previously not being correctly tested. If so, we will need to
narrow down which one.

BUG=706414

Review-Url: https://codereview.chromium.org/2778313003
Cr-Commit-Position: refs/heads/master@{#460498}

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():

tools/variations/fieldtrial_util_unittest.py

@@ -66,8 +66,8 @@ class FieldTrialUtilUnittest(unittest.TestCase):
         '--force-fieldtrial-params='
         'SimpleParams.Default:id/abc,'
         'c.d%2E:url/http%3A%2F%2Fwww%2Egoogle%2Ecom',
-        '--enable-features=a,b,x',
-        '--disable-features=y'], result)
+        '--enable-features="a<SimpleParams,b<SimpleParams,x<c"',
+        '--disable-features="y<c"'], result)
 
   def test_DuplicateEnableFeatures(self):
     config = '''{