[TTS] Add a Feature and about:flag for Single Actions.

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index dae17a73801308a0a11862a349a1b416ae4e99f7..c3c216919320dd17de0f93f7def17a4a5a90b7c3 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -90111,6 +90111,7 @@ value.
   <int value="550378029" label="reset-app-list-install-state"/>
   <int value="567368307" label="enable-experimental-canvas-features"/>
   <int value="581118445" label="enable-eol-notification"/>
+  <int value="584541349" label="ContextualSearchSingleActions:disabled"/>
   <int value="592050831" label="disable-slimming-paint"/>
   <int value="593707592" label="disable-network-portal-notification"/>
   <int value="598827460" label="enable-roboto-font-ui"/>
@@ -90386,6 +90387,7 @@ value.
   <int value="1896456311" label="enable-password-save-in-page-navigation"/>
   <int value="1898231011" label="enable-native-notifications"/>
   <int value="1900529524" label="disable-touch-drag-drop"/>
+  <int value="1905465678" label="ContextualSearchSingleActions:enabled"/>
   <int value="1906942630" label="enable-easy-unlock"/>
   <int value="1915178511" label="disable-blink-features"/>
   <int value="1927259098" label="TranslateLanguageByULP:enabled"/>