Split predictive back bitmask flags into a few boolean flags.

This is such that they can be controlled from Flag Flipper UI.

Boolean flags introduced:
persist.wm.debug.predictive_back - Overall switch for the new back infra
persist.wm.debug.predictive_back_anim - Animation switch
persist.wm.debug.predictive_back_always_enforce - Switch to ignore per
app opt-in flag and always enforce new behavior
persist.wm.debug.predictive_back_screenshot - Screenshot switch. Not
added to Flipper yet.

Test: Flip the flags in Flipper and verify behavior is as expected.

Change-Id: Icff098035119fb83f393e20c6ac590be2f22c845

core/java/android/window/WindowOnBackInvokedDispatcher.java

@@ -50,9 +50,10 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
     private IWindowSession mWindowSession;
     private IWindow mWindow;
     private static final String TAG = "WindowOnBackDispatcher";
-    private static final String BACK_PREDICTABILITY_PROP = "persist.debug.back_predictability";
-    private static final boolean IS_BACK_PREDICTABILITY_ENABLED = SystemProperties
-            .getInt(BACK_PREDICTABILITY_PROP, 1) > 0;
+    private static final boolean ENABLE_PREDICTIVE_BACK = SystemProperties
+            .getInt("persist.wm.debug.predictive_back", 1) != 0;
+    private static final boolean ALWAYS_ENFORCE_PREDICTIVE_BACK = SystemProperties
+            .getInt("persist.wm.debug.predictive_back_always_enforce", 0) != 0;
 
     /** Convenience hashmap to quickly decide if a callback has been added. */
     private final HashMap<OnBackInvokedCallback, Integer> mAllCallbacks = new HashMap<>();
@@ -249,18 +250,18 @@ public class WindowOnBackInvokedDispatcher implements OnBackInvokedDispatcher {
     public static boolean isOnBackInvokedCallbackEnabled(@Nullable Context context) {
         // new back is enabled if the feature flag is enabled AND the app does not explicitly
         // request legacy back.
-        boolean featureFlagEnabled = IS_BACK_PREDICTABILITY_ENABLED;
+        boolean featureFlagEnabled = ENABLE_PREDICTIVE_BACK;
         // If the context is null, we assume true and fallback on the two other conditions.
         boolean appRequestsPredictiveBack =
                 context != null && context.getApplicationInfo().isOnBackInvokedCallbackEnabled();
 
         if (DEBUG) {
             Log.d(TAG, TextUtils.formatSimple("App: %s featureFlagEnabled=%s "
-                            + "appRequestsPredictiveBack=%s",
+                            + "appRequestsPredictiveBack=%s alwaysEnforce=%s",
                     context != null ? context.getApplicationInfo().packageName : "null context",
-                    featureFlagEnabled, appRequestsPredictiveBack));
+                    featureFlagEnabled, appRequestsPredictiveBack, ALWAYS_ENFORCE_PREDICTIVE_BACK));
         }
 
-        return featureFlagEnabled && appRequestsPredictiveBack;
+        return featureFlagEnabled && (appRequestsPredictiveBack || ALWAYS_ENFORCE_PREDICTIVE_BACK);
     }
 }

libs/WindowManager/Shell/src/com/android/wm/shell/back/BackAnimationController.java

@@ -51,18 +51,16 @@ import com.android.wm.shell.common.annotations.ShellMainThread;
  * Controls the window animation run when a user initiates a back gesture.
  */
 public class BackAnimationController implements RemoteCallable<BackAnimationController> {
-
-    private static final String BACK_PREDICTABILITY_PROGRESS_THRESHOLD_PROP =
-            "persist.debug.back_predictability_progress_threshold";
-    // By default, enable new back dispatching without any animations.
-    private static final int BACK_PREDICTABILITY_PROP =
-            SystemProperties.getInt("persist.debug.back_predictability", 1);
-    public static final boolean IS_ENABLED = BACK_PREDICTABILITY_PROP > 0;
-    private static final int PROGRESS_THRESHOLD = SystemProperties
-            .getInt(BACK_PREDICTABILITY_PROGRESS_THRESHOLD_PROP, -1);
     private static final String TAG = "BackAnimationController";
+    private static final String PREDICTIVE_BACK_PROGRESS_THRESHOLD_PROP =
+            "persist.wm.debug.predictive_back_progress_threshold";
+    public static final boolean IS_ENABLED =
+            SystemProperties.getInt("persist.wm.debug.predictive_back", 1) != 0;
+    private static final int PROGRESS_THRESHOLD = SystemProperties
+            .getInt(PREDICTIVE_BACK_PROGRESS_THRESHOLD_PROP, -1);
     @VisibleForTesting
-    boolean mEnableAnimations = (BACK_PREDICTABILITY_PROP & (1 << 1)) != 0;
+    boolean mEnableAnimations = SystemProperties.getInt(
+            "persist.wm.debug.predictive_back_anim", 0) != 0;
 
     /**
      * Location of the initial touch event of the back gesture.

packages/SystemUI/src/com/android/systemui/flags/Flags.java

@@ -158,6 +158,17 @@ public class Flags {
     public static final SysPropBooleanFlag WM_ENABLE_SHELL_TRANSITIONS =
             new SysPropBooleanFlag(1100, "persist.wm.debug.shell_transit", false);
 
+    // 1200 - predictive back
+    @Keep
+    public static final SysPropBooleanFlag WM_ENABLE_PREDICTIVE_BACK = new SysPropBooleanFlag(
+            1200, "persist.wm.debug.predictive_back", true);
+    @Keep
+    public static final SysPropBooleanFlag WM_ENABLE_PREDICTIVE_BACK_ANIM = new SysPropBooleanFlag(
+            1201, "persist.wm.debug.predictive_back_anim", false);
+    @Keep
+    public static final SysPropBooleanFlag WM_ALWAYS_ENFORCE_PREDICTIVE_BACK =
+            new SysPropBooleanFlag(1202, "persist.wm.debug.predictive_back_always_enforce", false);
+
     // Pay no attention to the reflection behind the curtain.
     // ========================== Curtain ==========================
     // |                                                           |

services/core/java/com/android/server/wm/BackNavigationController.java

@@ -45,12 +45,6 @@ import com.android.internal.protolog.common.ProtoLog;
 class BackNavigationController {
 
     private static final String TAG = "BackNavigationController";
-    // By default, enable new back dispatching without any animations.
-    private static final int BACK_PREDICTABILITY_PROP =
-            SystemProperties.getInt("persist.debug.back_predictability", 1);
-    private static final int ANIMATIONS_MASK = 1 << 1;
-    private static final int SCREENSHOT_MASK = 1 << 2;
-
     @Nullable
     private TaskSnapshotController mTaskSnapshotController;
 
@@ -58,15 +52,15 @@ class BackNavigationController {
      * Returns true if the back predictability feature is enabled
      */
     static boolean isEnabled() {
-        return BACK_PREDICTABILITY_PROP > 0;
+        return SystemProperties.getInt("persist.wm.debug.predictive_back", 1) != 0;
     }
 
     static boolean isScreenshotEnabled() {
-        return (BACK_PREDICTABILITY_PROP & SCREENSHOT_MASK) != 0;
+        return SystemProperties.getInt("persist.wm.debug.predictive_back_screenshot", 0) != 0;
     }
 
     private static boolean isAnimationEnabled() {
-        return (BACK_PREDICTABILITY_PROP & ANIMATIONS_MASK) != 0;
+        return SystemProperties.getInt("persist.wm.debug.predictive_back_anim", 0) != 0;
     }
 
     /**