Move "Enable Boot Aware Startup data" to behind a FeatureFlag.

Previously this was hard-coded to disabled, but that was before
FeatureFlags were made to be boot aware.

Bug: 251502424
Test: Verified that doing this doesn't break my device. Also tested the
Pre-loading feature itself and didn't see any errors in the logs.

Change-Id: I031e1756b985664a2e8d8ad26e16803ead874727

src/com/android/launcher3/LauncherPrefs.kt

@@ -376,9 +376,10 @@ class LauncherPrefs(private val encryptedContext: Context) {
     }
 }
 
-// This is hard-coded to false for now until it is time to release this optimization. It is only
-// a var because the unit tests are setting this to true so they can run.
-@VisibleForTesting var isBootAwareStartupDataEnabled: Boolean = false
+// It is a var because the unit tests are setting this to true so they can run.
+@VisibleForTesting
+var isBootAwareStartupDataEnabled: Boolean =
+    com.android.launcher3.config.FeatureFlags.ENABLE_BOOT_AWARE_STARTUP_DATA.get()
 
 private val BOOT_AWARE_ITEMS: MutableSet<ConstantItem<*>> = mutableSetOf()
 

src/com/android/launcher3/config/FeatureFlags.java

@@ -265,6 +265,11 @@ public final class FeatureFlags {
             "Enables taskbar pinning to allow user to switch between transient and persistent "
                     + "taskbar flavors");
 
+    public static final BooleanFlag ENABLE_BOOT_AWARE_STARTUP_DATA = getDebugFlag(251502424,
+            "ENABLE_BOOT_AWARE_STARTUP_DATA", DISABLED, "Marks LauncherPref data as (and allows it "
+                    + "to) available while the device is locked. Enabling this causes a 1-time "
+                    + "migration of certain SharedPreferences data. Improves startup latency.");
+
     // TODO(Block 18): Clean up flags
     public static final BooleanFlag ENABLE_APP_PAIRS = getDebugFlag(274189428,
             "ENABLE_APP_PAIRS", DISABLED,