Omnibox UI Experiments: Add flag to change max autocomplete matches.

chrome/browser/about_flags.cc

 // Copyright (c) 2012 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 "chrome/browser/about_flags.h"
 
 #include <iterator>
 #include <map>
 #include <set>
 #include <utility>
@@ skipping 948 matching lines @@
 const FeatureEntry::Choice kEnableHeapProfilingChoices[] = {
     {flags_ui::kGenericExperimentChoiceDisabled, "", ""},
     {flag_descriptions::kEnableHeapProfilingModePseudo,
      switches::kEnableHeapProfiling, switches::kEnableHeapProfilingModePseudo},
     {flag_descriptions::kEnableHeapProfilingModeNative,
      switches::kEnableHeapProfiling, switches::kEnableHeapProfilingModeNative},
     {flag_descriptions::kEnableHeapProfilingTaskProfiler,
      switches::kEnableHeapProfiling,
      switches::kEnableHeapProfilingTaskProfiler}};
 
+const FeatureEntry::FeatureParam kOmniboxUIMaxAutocompleteMatches4[] = {
+    {OmniboxFieldTrial::kUIMaxAutocompleteMatchesParam, "4"}};
+const FeatureEntry::FeatureParam kOmniboxUIMaxAutocompleteMatches6[] = {
+    {OmniboxFieldTrial::kUIMaxAutocompleteMatchesParam, "6"}};
+const FeatureEntry::FeatureParam kOmniboxUIMaxAutocompleteMatches8[] = {
+    {OmniboxFieldTrial::kUIMaxAutocompleteMatchesParam, "8"}};
+const FeatureEntry::FeatureParam kOmniboxUIMaxAutocompleteMatches10[] = {
+    {OmniboxFieldTrial::kUIMaxAutocompleteMatchesParam, "10"}};
+const FeatureEntry::FeatureParam kOmniboxUIMaxAutocompleteMatches12[] = {
+    {OmniboxFieldTrial::kUIMaxAutocompleteMatchesParam, "12"}};

[Peter Kasting, 2017/05/10 22:08:05]

Why these choices?  There are no odd numbers, for one.  The bounds are a bit
extreme, but OK.

[tommycli, 2017/05/10 22:44:29]

Chosen pretty arbitrarily, since we can easily change the choices if these
default ones don't make sense. Happy to consider an alternative set.

+
+const FeatureEntry::FeatureVariation
+    kOmniboxUIMaxAutocompleteMatchesVariations[] = {
+        {"4 matches", kOmniboxUIMaxAutocompleteMatches4,
+         arraysize(kOmniboxUIMaxAutocompleteMatches4), nullptr},
+        {"6 matches", kOmniboxUIMaxAutocompleteMatches6,
+         arraysize(kOmniboxUIMaxAutocompleteMatches6), nullptr},
+        {"8 matches", kOmniboxUIMaxAutocompleteMatches8,
+         arraysize(kOmniboxUIMaxAutocompleteMatches8), nullptr},
+        {"10 matches", kOmniboxUIMaxAutocompleteMatches10,
+         arraysize(kOmniboxUIMaxAutocompleteMatches10), nullptr},
+        {"12 matches", kOmniboxUIMaxAutocompleteMatches12,
+         arraysize(kOmniboxUIMaxAutocompleteMatches12), nullptr}};
+
 const FeatureEntry::FeatureParam kOmniboxUIVerticalMargin4px[] = {
     {OmniboxFieldTrial::kUIVerticalMarginParam, "4"}};
 const FeatureEntry::FeatureParam kOmniboxUIVerticalMargin8px[] = {
     {OmniboxFieldTrial::kUIVerticalMarginParam, "8"}};
 const FeatureEntry::FeatureParam kOmniboxUIVerticalMargin12px[] = {
     {OmniboxFieldTrial::kUIVerticalMarginParam, "12"}};
 const FeatureEntry::FeatureParam kOmniboxUIVerticalMargin16px[] = {
     {OmniboxFieldTrial::kUIVerticalMarginParam, "16"}};
 const FeatureEntry::FeatureParam kOmniboxUIVerticalMargin20px[] = {
     {OmniboxFieldTrial::kUIVerticalMarginParam, "20"}};
@@ skipping 1874 matching lines @@
     {"enable-heap-profiling", flag_descriptions::kEnableHeapProfilingName,
      flag_descriptions::kEnableHeapProfilingDescription, kOsAll,
      MULTI_VALUE_TYPE(kEnableHeapProfilingChoices)},
 
 #if defined(TOOLKIT_VIEWS) || (defined(OS_MACOSX) && !defined(OS_IOS))
     {"show-cert-link", flag_descriptions::kShowCertLinkOnPageInfoName,
      flag_descriptions::kShowCertLinkOnPageInfoDescription, kOsDesktop,
      SINGLE_VALUE_TYPE(switches::kShowCertLink)},
 #endif
 
+    {"omnibox-ui-max-autocomplete-matches",
+     flag_descriptions::kOmniboxUIMaxAutocompleteMatchesName,
+     flag_descriptions::kOmniboxUIMaxAutocompleteMatchesDescription, kOsDesktop,
+     FEATURE_WITH_PARAMS_VALUE_TYPE(
+         omnibox::kUIExperimentMaxAutocompleteMatches,
+         kOmniboxUIMaxAutocompleteMatchesVariations,
+         "OmniboxUIMaxAutocompleteVariations")},
+
     {"omnibox-ui-vertical-margin",
      flag_descriptions::kOmniboxUIVerticalMarginName,
      flag_descriptions::kOmniboxUIVerticalMarginDescription, kOsDesktop,
      FEATURE_WITH_PARAMS_VALUE_TYPE(omnibox::kUIExperimentVerticalMargin,
                                     kOmniboxUIVerticalMarginVariations,
                                     "OmniboxUIVerticalMarginVariations")},
 
     {"use-suggestions-even-if-few",
      flag_descriptions::kUseSuggestionsEvenIfFewFeatureName,
      flag_descriptions::kUseSuggestionsEvenIfFewFeatureDescription, kOsAll,
@@ skipping 226 matching lines @@
 const base::HistogramBase::Sample kBadSwitchFormatHistogramId = 0;
 
 const FeatureEntry* GetFeatureEntries(size_t* count) {
   *count = arraysize(kFeatureEntries);
   return kFeatureEntries;
 }
 
 }  // namespace testing
 
 }  // namespace about_flags