Omnibox UI Experiments: Add vertical margin variations to about:flags

components/omnibox/browser/omnibox_field_trial.cc

 // Copyright 2014 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/omnibox/browser/omnibox_field_trial.h"
 
 #include <cmath>
 #include <string>
 
 #include "base/command_line.h"
@@ skipping 62 matching lines @@
 
 // Feature used to swap the title and URL when providing zero suggest
 // suggestions.
 const base::Feature kZeroSuggestSwapTitleAndUrl{
     "ZeroSuggestSwapTitleAndUrl", base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Feature used to display the title of the current URL match.
 const base::Feature kDisplayTitleForCurrentUrl{
     "OmniboxDisplayTitleForCurrentUrl", base::FEATURE_DISABLED_BY_DEFAULT};
 
+// Feature used for UI experiments.
+const base::Feature kUIExperiments{"OmniboxUIExperiments",
+                                   base::FEATURE_DISABLED_BY_DEFAULT};
+
 }  // namespace omnibox
 
 namespace {
 
 typedef std::map<std::string, std::string> VariationParams;
 typedef HUPScoringParams::ScoreBuckets ScoreBuckets;
 
 // Field trial names.
 const char kStopTimerFieldTrialName[] = "OmniboxStopTimer";
 
@@ skipping 636 matching lines @@
     "PhysicalWebZeroSuggestBaseRelevance";
 const char OmniboxFieldTrial::kPhysicalWebAfterTypingBaseRelevanceParam[] =
     "PhysicalWebAfterTypingBaseRelevanceParam";
 
 const char OmniboxFieldTrial::kZeroSuggestRedirectToChromeServerAddressParam[] =
     "ZeroSuggestRedirectToChromeServerAddress";
 const char
     OmniboxFieldTrial::kZeroSuggestRedirectToChromeAdditionalFieldsParam[] =
         "ZeroSuggestRedirectToChromeAdditionalFields";
 
+const char OmniboxFieldTrial::kUIExperimentsVerticalMarginParam[] =
+    "UIExperimentsVerticalMargin";
+
 // static
 int OmniboxFieldTrial::kDefaultMinimumTimeBetweenSuggestQueriesMs = 100;
 
 // Background and implementation details:
 //
 // Each experiment group in any field trial can come with an optional set of
 // parameters (key-value pairs).  In the bundled omnibox experiment
 // (kBundledExperimentFieldTrialName), each experiment group comes with a
 // list of parameters in the form:
 //   key=<Rule>:
@@ skipping 45 matching lines @@
   if (it != params.end())
     return it->second;
   // Fall back to the global instant extended context.
   it = params.find(rule + ":" + page_classification_str + ":*");
   if (it != params.end())
     return it->second;
   // Look up rule in the global context.
   it = params.find(rule + ":*:*");
   return (it != params.end()) ? it->second : std::string();
 }