Setup controller for on device search

With introduction of feature flag ENABLE_DEVICE_SEARCH, Launcher can now show a softkey input when user goes to all apps.

Bug: 161545076
Test: Manual
Change-Id: Ie75d059da0a20d0fb98b87bb948a205c080ba529
diff --git a/src/com/android/launcher3/config/FeatureFlags.java b/src/com/android/launcher3/config/FeatureFlags.java
index 5c4a492..78e8b82 100644
--- a/src/com/android/launcher3/config/FeatureFlags.java
+++ b/src/com/android/launcher3/config/FeatureFlags.java
@@ -94,6 +94,10 @@
     public static final BooleanFlag ENABLE_SUGGESTED_ACTIONS_OVERVIEW = new DeviceFlag(
             "ENABLE_SUGGESTED_ACTIONS_OVERVIEW", false, "Show chip hints on the overview screen");
 
+
+    public static final BooleanFlag ENABLE_DEVICE_SEARCH = getDebugFlag(
+            "ENABLE_DEVICE_SEARCH", false, "Allows on device search in all apps");
+
     public static final BooleanFlag FOLDER_NAME_SUGGEST = new DeviceFlag(
             "FOLDER_NAME_SUGGEST", true,
             "Suggests folder names instead of blank text.");