[omnibox] Add flags for enabling and setting max URL suggestions

This CL only adds a flag with parameter for enabling capping the
number of URL suggestions, and configuring the limit.

Bug: 963174
Change-Id: I5d4310cf361dc5af1df734b8ff433720eef10fc0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1635435
Commit-Queue: Kevin Bailey <krb@chromium.org>
Reviewed-by: Justin Donnelly <jdonnelly@chromium.org>
Cr-Commit-Position: refs/heads/master@{#664781}

chrome/browser/about_flags.cc

@@ -751,6 +751,29 @@ const FeatureEntry::FeatureVariation
         {"12 matches", kOmniboxUIMaxAutocompleteMatches12,
          base::size(kOmniboxUIMaxAutocompleteMatches12), nullptr}};
 
+const FeatureEntry::FeatureParam kOmniboxMaxURLMatches2[] = {
+    {OmniboxFieldTrial::kOmniboxMaxURLMatchesParam, "2"}};
+const FeatureEntry::FeatureParam kOmniboxMaxURLMatches3[] = {
+    {OmniboxFieldTrial::kOmniboxMaxURLMatchesParam, "3"}};
+const FeatureEntry::FeatureParam kOmniboxMaxURLMatches4[] = {
+    {OmniboxFieldTrial::kOmniboxMaxURLMatchesParam, "4"}};
+const FeatureEntry::FeatureParam kOmniboxMaxURLMatches5[] = {
+    {OmniboxFieldTrial::kOmniboxMaxURLMatchesParam, "5"}};
+const FeatureEntry::FeatureParam kOmniboxMaxURLMatches6[] = {
+    {OmniboxFieldTrial::kOmniboxMaxURLMatchesParam, "6"}};
+
+const FeatureEntry::FeatureVariation kOmniboxMaxURLMatchesVariations[] = {
+    {"2 matches", kOmniboxMaxURLMatches2, base::size(kOmniboxMaxURLMatches2),
+     nullptr},
+    {"3 matches", kOmniboxMaxURLMatches3, base::size(kOmniboxMaxURLMatches3),
+     nullptr},
+    {"4 matches", kOmniboxMaxURLMatches4, base::size(kOmniboxMaxURLMatches4),
+     nullptr},
+    {"5 matches", kOmniboxMaxURLMatches5, base::size(kOmniboxMaxURLMatches5),
+     nullptr},
+    {"6 matches", kOmniboxMaxURLMatches6, base::size(kOmniboxMaxURLMatches6),
+     nullptr}};
+
 #if defined(OS_LINUX) || defined(OS_MACOSX) || defined(OS_WIN) || \
     defined(OS_CHROMEOS)
 const FeatureEntry::FeatureParam kTranslateBubbleUIButton[] = {
@@ -2532,6 +2555,12 @@ const FeatureEntry kFeatureEntries[] = {
          kOmniboxUIMaxAutocompleteMatchesVariations,
          "OmniboxUIMaxAutocompleteVariations")},
 
+    {"omnibox-max-url-matches", flag_descriptions::kOmniboxMaxURLMatchesName,
+     flag_descriptions::kOmniboxMaxURLMatchesDescription, kOsAll,
+     FEATURE_WITH_PARAMS_VALUE_TYPE(omnibox::kOmniboxMaxURLMatches,
+                                    kOmniboxMaxURLMatchesVariations,
+                                    "OmniboxMaxURLMatchesVariations")},
+
     {"omnibox-ui-vertical-margin",
      flag_descriptions::kOmniboxUIVerticalMarginName,
      flag_descriptions::kOmniboxUIVerticalMarginDescription, kOsDesktop,

chrome/browser/flag-metadata.json

@@ -2400,6 +2400,11 @@
     "owners": [ "manukh", "chromium-omnibox-team" ],
     "expiry_milestone": 76
   },
+  {
+    "name": "omnibox-max-url-matches",
+    "owners": [ "krb", "chromium-omnibox-team" ],
+    "expiry_milestone": 80
+  },
   {
     "name": "omnibox-new-answer-layout",
     "owners": [ "chrome-omnibox-team@google.com" ],

chrome/browser/flag_descriptions.cc

@@ -1309,6 +1309,11 @@ const char kOmniboxUIMaxAutocompleteMatchesDescription[] =
     "Changes the maximum number of autocomplete matches displayed in the "
     "Omnibox UI.";
 
+const char kOmniboxMaxURLMatchesName[] = "Omnibox Max URL Matches";
+const char kOmniboxMaxURLMatchesDescription[] =
+    "The maximum number of URL matches to show, unless there are no "
+    "replacements.";
+
 const char kOmniboxUIShowPlaceholderWhenCaretShowingName[] =
     "Omnibox UI Show Placeholder When Caret Showing";
 const char kOmniboxUIShowPlaceholderWhenCaretShowingDescription[] =

chrome/browser/flag_descriptions.h

@@ -797,6 +797,9 @@ extern const char kOmniboxUIOneClickUnelideDescription[];
 extern const char kOmniboxUIMaxAutocompleteMatchesName[];
 extern const char kOmniboxUIMaxAutocompleteMatchesDescription[];
 
+extern const char kOmniboxMaxURLMatchesName[];
+extern const char kOmniboxMaxURLMatchesDescription[];
+
 extern const char kOmniboxUIShowPlaceholderWhenCaretShowingName[];
 extern const char kOmniboxUIShowPlaceholderWhenCaretShowingDescription[];
 

components/omnibox/browser/autocomplete_result.cc

@@ -181,7 +181,7 @@ void AutocompleteResult::SortAndCull(
     std::rotate(matches_.begin(), it, it + 1);
 
   size_t max_url_count = 0;
-  if (OmniboxFieldTrial::IsCapURLMatchesFeatureEnabled() &&
+  if (OmniboxFieldTrial::IsMaxURLMatchesFeatureEnabled() &&
       (max_url_count = OmniboxFieldTrial::GetMaxURLMatches()) != 0)
     LimitNumberOfURLsShown(max_url_count, comparing_object);
 

components/omnibox/browser/autocomplete_result_unittest.cc

@@ -1049,13 +1049,13 @@ TEST_F(AutocompleteResultTest, SortAndCullGroupSuggestionsByType) {
   AssertResultMatches(result, expected_data, base::size(expected_data));
 }
 
-TEST_F(AutocompleteResultTest, SortAndCullCapURLMatches) {
+TEST_F(AutocompleteResultTest, SortAndCullMaxURLMatches) {
   base::test::ScopedFeatureList feature_list;
   std::map<std::string, std::string> parameters = {
       {OmniboxFieldTrial::kOmniboxMaxURLMatchesParam, "3"}};
   feature_list.InitAndEnableFeatureWithParameters(
-      omnibox::kOmniboxCapURLMatches, parameters);
-  EXPECT_TRUE(OmniboxFieldTrial::IsCapURLMatchesFeatureEnabled());
+      omnibox::kOmniboxMaxURLMatches, parameters);
+  EXPECT_TRUE(OmniboxFieldTrial::IsMaxURLMatchesFeatureEnabled());
   EXPECT_EQ(OmniboxFieldTrial::GetMaxURLMatches(), 3u);
 
   // Case 1: Eject URL match for a search.

components/omnibox/browser/omnibox_field_trial.cc

@@ -649,7 +649,7 @@ OmniboxFieldTrial::GetEmphasizeTitlesConditionForInput(
 
 size_t OmniboxFieldTrial::GetMaxURLMatches() {
   return base::GetFieldTrialParamByFeatureAsInt(
-      omnibox::kOmniboxCapURLMatches,
+      omnibox::kOmniboxMaxURLMatches,
       OmniboxFieldTrial::kOmniboxMaxURLMatchesParam,
       0);  // default
 }
@@ -716,8 +716,8 @@ bool OmniboxFieldTrial::IsGroupSuggestionsBySearchVsUrlFeatureEnabled() {
       omnibox::kOmniboxGroupSuggestionsBySearchVsUrl);
 }
 
-bool OmniboxFieldTrial::IsCapURLMatchesFeatureEnabled() {
-  return base::FeatureList::IsEnabled(omnibox::kOmniboxCapURLMatches);
+bool OmniboxFieldTrial::IsMaxURLMatchesFeatureEnabled() {
+  return base::FeatureList::IsEnabled(omnibox::kOmniboxMaxURLMatches);
 }
 
 const char OmniboxFieldTrial::kBundledExperimentFieldTrialName[] =

components/omnibox/browser/omnibox_field_trial.h

@@ -439,7 +439,7 @@ bool IsGroupSuggestionsBySearchVsUrlFeatureEnabled();
 
 // Returns whether the feature to limit the number of shown URL matches
 // is enabled.
-bool IsCapURLMatchesFeatureEnabled();
+bool IsMaxURLMatchesFeatureEnabled();
 
 // ---------------------------------------------------------
 // Clipboard URL suggestions:

components/omnibox/common/omnibox_features.cc

@@ -85,7 +85,7 @@ const base::Feature kOmniboxLocalEntitySuggestions{
 // there are no more non-URL matches available.) If enabled, there is a
 // companion parameter - OmniboxMaxURLMatches - which specifies the maximum
 // desired number of URL-type matches.
-const base::Feature kOmniboxCapURLMatches{"OmniboxCapURLMatches",
+const base::Feature kOmniboxMaxURLMatches{"OmniboxMaxURLMatches",
                                           base::FEATURE_DISABLED_BY_DEFAULT};
 
 // Feature used to enable entity suggestion images and enhanced presentation

components/omnibox/common/omnibox_features.h

@@ -18,7 +18,7 @@ extern const base::Feature kOneClickUnelide;
 extern const base::Feature kSimplifyHttpsIndicator;
 extern const base::Feature kOmniboxGroupSuggestionsBySearchVsUrl;
 extern const base::Feature kOmniboxLocalEntitySuggestions;
-extern const base::Feature kOmniboxCapURLMatches;
+extern const base::Feature kOmniboxMaxURLMatches;
 extern const base::Feature kOmniboxRichEntitySuggestions;
 extern const base::Feature kOmniboxNewAnswerLayout;
 extern const base::Feature kOmniboxReverseAnswers;

tools/metrics/histograms/enums.xml

@@ -32974,6 +32974,7 @@ Called by update_gpu_driver_bug_workaround_entries.py.-->
 </enum>
 
 <enum name="LoginCustomFlags">
+  <int value="-2146979021" label="OmniboxMaxURLMatches:enabled"/>
   <int value="-2146832142" label="SyncPseudoUSSSearchEngines:enabled"/>
   <int value="-2146613579" label="V8Future:disabled"/>
   <int value="-2145472146" label="OfflinePagesResourceBasedSnapshot:disabled"/>
@@ -35750,6 +35751,7 @@ from previous Chrome versions.
   <int value="1950191981" label="OverlayNewLayout:enabled"/>
   <int value="1951466218" label="enable-data-reduction-proxy-lite-page"/>
   <int value="1951645673" label="PasswordsKeyboardAccessory:disabled"/>
+  <int value="1955238689" label="OmniboxMaxURLMatches:disabled"/>
   <int value="1957273171" label="PageAlmostIdle:disabled"/>
   <int value="1957358530" label="ContextualSearchSecondTap:enabled"/>
   <int value="1957472162"