enable/disable dexopt for instant apps remotely

Change-Id: I997b8ae515f7bf2570edca4ed7ab4b46198148a5
Fixes: 62591398
Test: Manual; install instant app and see that it doesn't dexopt
Test: Manua; update gservices flag, install instant app and see that it does dexopt

core/java/android/provider/Settings.java

@@ -9817,6 +9817,16 @@ public final class Settings {
          */
         public static final String ENABLE_EPHEMERAL_FEATURE = "enable_ephemeral_feature";
 
+        /**
+         * Toggle to enable/disable dexopt for instant applications. The default is for dexopt
+         * to be disabled.
+         * <p>
+         * Type: int (0 to disable, 1 to enable)
+         *
+         * @hide
+         */
+        public static final String INSTANT_APP_DEXOPT_ENABLED = "instant_app_dexopt_enabled";
+
         /**
          * The min period for caching installed instant apps in milliseconds.
          * <p>

services/core/java/com/android/server/pm/PackageManagerService.java

@@ -18160,8 +18160,10 @@ public class PackageManagerService extends IPackageManager.Stub
             // step during installation. Instead, we'll take extra time the first time the
             // instant app starts. It's preferred to do it this way to provide continuous
             // progress to the user instead of mysteriously blocking somewhere in the
-            // middle of running an instant app.
-            if (!instantApp) {
+            // middle of running an instant app. The default behaviour can be overridden
+            // via gservices.
+            if (!instantApp || Global.getInt(
+                        mContext.getContentResolver(), Global.INSTANT_APP_DEXOPT_ENABLED, 0) != 0) {
                 Trace.traceBegin(TRACE_TAG_PACKAGE_MANAGER, "dexopt");
                 // Do not run PackageDexOptimizer through the local performDexOpt
                 // method because `pkg` may not be in `mPackages` yet.