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

tools/metrics/histograms/enums.xml

Index: tools/metrics/histograms/enums.xml
diff --git a/tools/metrics/histograms/enums.xml b/tools/metrics/histograms/enums.xml
index 7cd3d14b75192295da97066d018c4c17598b600a..7c04b7fd75119d979f3eb5db9a5af8e2c75eac6f 100644
--- a/tools/metrics/histograms/enums.xml
+++ b/tools/metrics/histograms/enums.xml
@@ -21651,6 +21651,8 @@ from previous Chrome versions.
   <int value="98134240" label="material-design-ink-drop-animation-speed"/>
   <int value="103932290" label="show-autofill-type-predictions"/>
   <int value="118991027" label="enable-accelerated-fixed-root-background"/>
+  <int value="119185738"
+      label="OmniboxUIExperimentMaxAutocompleteMatches:disabled"/>
   <int value="120429808" label="disable-new-profile-management"/>
   <int value="121684313" label="QuickUnlockPin:enabled"/>
   <int value="121858954" label="enable-supervised-user-safesites"/>
@@ -21921,6 +21923,8 @@ from previous Chrome versions.
   <int value="1166169237" label="disable-delay-agnostic-aec"/>
   <int value="1167613030" label="enable-permission-action-reporting"/>
   <int value="1174088940" label="enable-wasm"/>
+  <int value="1179013979"
+      label="OmniboxUIExperimentMaxAutocompleteMatches:enabled"/>
   <int value="1179936481" label="enable-android-pay-integration-v1"/>
   <int value="1181056275" label="enable-cloud-backup"/>
   <int value="1183431946" label="v8-cache-options"/>