[Hotword] Putting preferences under search for hotword service. Putting behind a flag.

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 0b8cace3896e5d93741d62cf43363eb8a5477bd0..c077d3d1b16291fe7a895ad6d518d884fa7439fb 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -2153,6 +2153,11 @@ const char kHotwordSearchEnabled[] = "hotword.search_enabled";
 const char kHotwordSearchIncognitoEnabled[] =
     "hotword.incognito_search_enabled";
 
+// A boolean pref that controls whether hotword search voice trigger stops
+// listening after 5 minutes.
+const char kHotwordSearchTimeoutEnabled[] =
+    "hotword.search_timeout_enabled";
+
 #if defined(OS_ANDROID)
 // Boolean that controls the global enabled-state of protected media identifier.
 const char kProtectedMediaIdentifierEnabled[] =