Fine tuned availability of hotword plugin.

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 83af1f5d68dcfef7110dba596d8f271f43f7028f..8b0f307d85001b7fb9a45d7ed2618c2d8db753af 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -2105,6 +2105,13 @@ const char kHotwordSearchEnabled[] = "hotword.search_enabled";
 // longer shown.
 const char kHotwordOptInPopupTimesShown[] = "hotword.opt_in_popup_times_shown";
 
+#if defined(OS_CHROMEOS)
+// A boolean pref that controls the enabled-state of hotword search in the
+// app-list. This pref cooperates with kHotwordSearchEnabled. If the user
+// explicitly turns off kHotwordSearchEnabled, this pref should go off too.
+const char kHotwordAppListEnabled[] = "hotword.app_list_enabled";
+#endif
+
 #if defined(OS_ANDROID)
 // Boolean that controls the global enabled-state of protected media identifier.
 const char kProtectedMediaIdentifierEnabled[] =