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

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 059fe8234236edfad9fce6c86552575ba59fefa1..7059339706703340f7f4f1c662b41e2124c9949b 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -966,6 +966,30 @@ const FeatureEntry::Choice kEnableHeapProfilingChoices[] = {
      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[] = {
@@ -2860,6 +2884,14 @@ const FeatureEntry kFeatureEntries[] = {
      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,