Added PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS window flag.

When a window with this flag is visible, then any other window added
by an application process that requires OP_SYSTEM_ALERT_WINDOW
permission or that are of TYPE_TOAST will be hidden.

Bug: 62196835
Test: go/wm-smoke
Test: Added the new flag to the RecentsActivity onCreate, launched FB
chat heads and observed the head head become invisible when Recents is
visible and the chat head become visible when Recents is no longer
visible.

Change-Id: I1a3e3c5b1696a5f5b95eac187acb5a03863b4a0b

8 files changed, 107 insertions, 18 deletions

diff --git a/api/system-current.txt b/api/system-current.txt
index 12d3d9697e70..b8ad4cb0303b 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -120,6 +120,7 @@ package android {
     field public static final java.lang.String GRANT_RUNTIME_PERMISSIONS = "android.permission.GRANT_RUNTIME_PERMISSIONS";
     field public static final java.lang.String HARDWARE_TEST = "android.permission.HARDWARE_TEST";
     field public static final java.lang.String HDMI_CEC = "android.permission.HDMI_CEC";
+    field public static final java.lang.String HIDE_NON_SYSTEM_OVERLAY_WINDOWS = "android.permission.HIDE_NON_SYSTEM_OVERLAY_WINDOWS";
     field public static final java.lang.String INJECT_EVENTS = "android.permission.INJECT_EVENTS";
     field public static final java.lang.String INSTALL_GRANT_RUNTIME_PERMISSIONS = "android.permission.INSTALL_GRANT_RUNTIME_PERMISSIONS";
     field public static final java.lang.String INSTALL_LOCATION_PROVIDER = "android.permission.INSTALL_LOCATION_PROVIDER";
diff --git a/core/java/android/view/WindowManager.java b/core/java/android/view/WindowManager.java
index 3fd459958ed4..050aa4d66c14 100644
--- a/core/java/android/view/WindowManager.java
+++ b/core/java/android/view/WindowManager.java
@@ -1403,15 +1403,14 @@ public interface WindowManager extends ViewManager {
         public static final int PRIVATE_FLAG_SUSTAINED_PERFORMANCE_MODE = 0x00040000;
 
         /**
-         * Flag to indicate that this window is used as a task snapshot window. A task snapshot
-         * window is a starting window that gets shown with a screenshot from the previous state
-         * that is active until the app has drawn its first frame.
-         *
-         * <p>If this flag is set, SystemUI flags are ignored such that the real window behind can
-         * set the SystemUI flags.
+         * Flag to indicate that any window added by an application process that is of type
+         * {@link #TYPE_TOAST} or that requires
+         * {@link android.app.AppOpsManager#OP_SYSTEM_ALERT_WINDOW} permission should be hidden when
+         * this window is visible.
          * @hide
          */
-        public static final int PRIVATE_FLAG_TASK_SNAPSHOT = 0x00080000;
+        @RequiresPermission(android.Manifest.permission.HIDE_NON_SYSTEM_OVERLAY_WINDOWS)
+        public static final int PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS = 0x00080000;
 
         /**
          * Flag to indicate that this window should be ignored when determining what parts of the
diff --git a/core/res/AndroidManifest.xml b/core/res/AndroidManifest.xml
index be7934ba3fe5..6fa91abf71a5 100644
--- a/core/res/AndroidManifest.xml
+++ b/core/res/AndroidManifest.xml
@@ -2394,6 +2394,15 @@
     <permission android:name="android.permission.INTERNAL_SYSTEM_WINDOW"
         android:protectionLevel="signature" />
 
+    <!-- @SystemApi Allows an application to use
+         {@link android.view.WindowManager.LayoutsParams#PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS}
+         to hide non-system-overlay windows.
+         <p>Not for use by third-party applications.
+         @hide
+    -->
+    <permission android:name="android.permission.HIDE_NON_SYSTEM_OVERLAY_WINDOWS"
+                android:protectionLevel="signature|installer" />
+
     <!-- @SystemApi Allows an application to manage (create, destroy,
          Z-order) application tokens in the window manager.
          <p>Not for use by third-party applications.
diff --git a/services/core/java/com/android/server/wm/Session.java b/services/core/java/com/android/server/wm/Session.java
index 22b0f5bcdf07..7a8c2f91b4e9 100644
--- a/services/core/java/com/android/server/wm/Session.java
+++ b/services/core/java/com/android/server/wm/Session.java
@@ -16,6 +16,7 @@
 
 package com.android.server.wm;
 
+import static android.Manifest.permission.HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
 import static android.Manifest.permission.INTERNAL_SYSTEM_WINDOW;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.os.Trace.TRACE_TAG_WINDOW_MANAGER;
@@ -82,6 +83,7 @@ public class Session extends IWindowSession.Stub
     // Set of visible alert window surfaces connected to this session.
     private final Set<WindowSurfaceController> mAlertWindowSurfaces = new HashSet<>();
     final boolean mCanAddInternalSystemWindow;
+    final boolean mCanHideNonSystemOverlayWindows;
     private AlertWindowNotification mAlertWindowNotification;
     private boolean mShowingAlertWindowNotificationAllowed;
     private boolean mClientDead = false;
@@ -99,6 +101,8 @@ public class Session extends IWindowSession.Stub
         mLastReportedAnimatorScale = service.getCurrentAnimatorScale();
         mCanAddInternalSystemWindow = service.mContext.checkCallingOrSelfPermission(
                 INTERNAL_SYSTEM_WINDOW) == PERMISSION_GRANTED;
+        mCanHideNonSystemOverlayWindows = service.mContext.checkCallingOrSelfPermission(
+                HIDE_NON_SYSTEM_OVERLAY_WINDOWS) == PERMISSION_GRANTED;
         mShowingAlertWindowNotificationAllowed = mService.mShowAlertWindowNotifications;
         StringBuilder sb = new StringBuilder();
         sb.append("Session{");
diff --git a/services/core/java/com/android/server/wm/TaskSnapshotSurface.java b/services/core/java/com/android/server/wm/TaskSnapshotSurface.java
index a96d22412918..249620131867 100644
--- a/services/core/java/com/android/server/wm/TaskSnapshotSurface.java
+++ b/services/core/java/com/android/server/wm/TaskSnapshotSurface.java
@@ -32,7 +32,6 @@ import static android.view.WindowManager.LayoutParams.FLAG_SLIPPERY;
 import static android.view.WindowManager.LayoutParams.FLAG_SPLIT_TOUCH;
 import static android.view.WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH;
 import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_FORCE_DRAW_STATUS_BAR_BACKGROUND;
-import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_TASK_SNAPSHOT;
 import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION_STARTING;
 import static com.android.internal.policy.DecorView.NAVIGATION_BAR_COLOR_VIEW_ATTRIBUTES;
 import static com.android.internal.policy.DecorView.STATUS_BAR_COLOR_VIEW_ATTRIBUTES;
@@ -164,8 +163,7 @@ class TaskSnapshotSurface implements StartingSurface {
             layoutParams.flags = (windowFlags & ~FLAG_INHERIT_EXCLUDES)
                     | FLAG_NOT_FOCUSABLE
                     | FLAG_NOT_TOUCHABLE;
-            layoutParams.privateFlags = PRIVATE_FLAG_TASK_SNAPSHOT
-                    | (windowPrivateFlags & PRIVATE_FLAG_INHERITS);
+            layoutParams.privateFlags = windowPrivateFlags & PRIVATE_FLAG_INHERITS;
             layoutParams.token = token.token;
             layoutParams.width = LayoutParams.MATCH_PARENT;
             layoutParams.height = LayoutParams.MATCH_PARENT;
diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index ceddc4e23fe5..afcd0157ff2d 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -30,7 +30,6 @@ import static android.content.pm.PackageManager.PERMISSION_GRANTED;
 import static android.os.Process.ROOT_UID;
 import static android.os.Process.SHELL_UID;
 import static android.os.Process.SYSTEM_UID;
-import static android.os.Process.THREAD_PRIORITY_DISPLAY;
 import static android.os.Process.myPid;
 import static android.os.Trace.TRACE_TAG_WINDOW_MANAGER;
 import static android.os.UserHandle.USER_NULL;
@@ -50,7 +49,6 @@ import static android.view.WindowManager.LayoutParams.INPUT_FEATURE_NO_INPUT_CHA
 import static android.view.WindowManager.LayoutParams.LAST_APPLICATION_WINDOW;
 import static android.view.WindowManager.LayoutParams.LAST_SUB_WINDOW;
 import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_COMPATIBLE_WINDOW;
-import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_TASK_SNAPSHOT;
 import static android.view.WindowManager.LayoutParams.TYPE_ACCESSIBILITY_OVERLAY;
 import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION_STARTING;
 import static android.view.WindowManager.LayoutParams.TYPE_DOCK_DIVIDER;
@@ -233,7 +231,6 @@ import com.android.server.DisplayThread;
 import com.android.server.EventLogTags;
 import com.android.server.FgThread;
 import com.android.server.LocalServices;
-import com.android.server.ThreadPriorityBooster;
 import com.android.server.UiThread;
 import com.android.server.Watchdog;
 import com.android.server.input.InputManagerService;
@@ -498,12 +495,15 @@ public class WindowManagerService extends IWindowManager.Stub
      */
     Runnable mWaitingForDrawnCallback;
 
+    /** List of window currently causing non-system overlay windows to be hidden. */
+    private ArrayList<WindowState> mHidingNonSystemOverlayWindows = new ArrayList<>();
+
     /**
      * Stores for each user whether screencapture is disabled
      * This array is essentially a cache for all userId for
      * {@link android.app.admin.DevicePolicyManager#getScreenCaptureDisabled}
      */
-    SparseArray<Boolean> mScreenCaptureDisabled = new SparseArray<>();
+    private SparseArray<Boolean> mScreenCaptureDisabled = new SparseArray<>();
 
     IInputMethodManager mInputMethodManager;
 
@@ -1718,6 +1718,7 @@ public class WindowManagerService extends IWindowManager.Stub
         }
         mPendingRemove.remove(win);
         mResizingWindows.remove(win);
+        updateNonSystemOverlayWindowsVisibilityIfNeeded(win, false /* surfaceShown */);
         mWindowsChanged = true;
         if (DEBUG_WINDOW_MOVEMENT) Slog.v(TAG_WM, "Final remove of window: " + win);
 
@@ -6479,6 +6480,21 @@ public class WindowManagerService extends IWindowManager.Stub
             ArrayList<WindowState> windows) {
         mRoot.dumpWindowsNoHeader(pw, dumpAll, windows);
 
+        if (!mHidingNonSystemOverlayWindows.isEmpty()) {
+            pw.println();
+            pw.println("  Hiding System Alert Windows:");
+            for (int i = mHidingNonSystemOverlayWindows.size() - 1; i >= 0; i--) {
+                final WindowState w = mHidingNonSystemOverlayWindows.get(i);
+                pw.print("  #"); pw.print(i); pw.print(' ');
+                pw.print(w);
+                if (dumpAll) {
+                    pw.println(":");
+                    w.dump(pw, "    ", true);
+                } else {
+                    pw.println();
+                }
+            }
+        }
         if (mPendingRemove.size() > 0) {
             pw.println();
             pw.println("  Remove pending for:");
@@ -7593,4 +7609,28 @@ public class WindowManagerService extends IWindowManager.Stub
     boolean hasWideColorGamutSupport() {
         return mHasWideColorGamutSupport;
     }
+
+    void updateNonSystemOverlayWindowsVisibilityIfNeeded(WindowState win, boolean surfaceShown) {
+        if (!win.hideNonSystemOverlayWindowsWhenVisible()) {
+            return;
+        }
+        final boolean systemAlertWindowsHidden = !mHidingNonSystemOverlayWindows.isEmpty();
+        if (surfaceShown) {
+            if (!mHidingNonSystemOverlayWindows.contains(win)) {
+                mHidingNonSystemOverlayWindows.add(win);
+            }
+        } else {
+            mHidingNonSystemOverlayWindows.remove(win);
+        }
+
+        final boolean hideSystemAlertWindows = !mHidingNonSystemOverlayWindows.isEmpty();
+
+        if (systemAlertWindowsHidden == hideSystemAlertWindows) {
+            return;
+        }
+
+        mRoot.forAllWindows((w) -> {
+            w.setForceHideNonSystemOverlayWindowIfNeeded(hideSystemAlertWindows);
+        }, false /* traverseTopToBottom */);
+    }
 }
diff --git a/services/core/java/com/android/server/wm/WindowState.java b/services/core/java/com/android/server/wm/WindowState.java
index f74948f8e7f0..464743ada28d 100644
--- a/services/core/java/com/android/server/wm/WindowState.java
+++ b/services/core/java/com/android/server/wm/WindowState.java
@@ -46,6 +46,7 @@ import static android.view.WindowManager.LayoutParams.FORMAT_CHANGED;
 import static android.view.WindowManager.LayoutParams.LAST_SUB_WINDOW;
 import static android.view.WindowManager.LayoutParams.MATCH_PARENT;
 import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_COMPATIBLE_WINDOW;
+import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS;
 import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_LAYOUT_CHILD_WINDOW_IN_PARENT_FRAME;
 import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_NO_MOVE_ANIMATION;
 import static android.view.WindowManager.LayoutParams.PRIVATE_FLAG_WILL_NOT_REPLACE_ON_RELAUNCH;
@@ -59,7 +60,9 @@ import static android.view.WindowManager.LayoutParams.TYPE_DOCK_DIVIDER;
 import static android.view.WindowManager.LayoutParams.TYPE_DRAWN_APPLICATION;
 import static android.view.WindowManager.LayoutParams.TYPE_INPUT_METHOD;
 import static android.view.WindowManager.LayoutParams.TYPE_INPUT_METHOD_DIALOG;
+import static android.view.WindowManager.LayoutParams.TYPE_TOAST;
 import static android.view.WindowManager.LayoutParams.TYPE_WALLPAPER;
+import static android.view.WindowManager.LayoutParams.isSystemAlertWindowType;
 import static android.view.WindowManagerGlobal.RELAYOUT_RES_DRAG_RESIZING_DOCKED;
 import static android.view.WindowManagerGlobal.RELAYOUT_RES_DRAG_RESIZING_FREEFORM;
 import static android.view.WindowManagerGlobal.RELAYOUT_RES_FIRST_TIME;
@@ -208,6 +211,8 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
     boolean mPolicyVisibilityAfterAnim = true;
     private boolean mAppOpVisibility = true;
     boolean mPermanentlyHidden; // the window should never be shown again
+    // This is a non-system overlay window that is currently force hidden.
+    private boolean mForceHideNonSystemOverlayWindow;
     boolean mAppFreezing;
     boolean mHidden;    // Used to determine if to show child windows.
     boolean mWallpaperVisible;  // for wallpaper, what was last vis report?
@@ -2371,6 +2376,10 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
             // to handle their windows being removed from under them.
             return false;
         }
+        if (mForceHideNonSystemOverlayWindow) {
+            // This is an alert window that is currently force hidden.
+            return false;
+        }
         if (mPolicyVisibility && mPolicyVisibilityAfterAnim) {
             // Already showing.
             return false;
@@ -2447,6 +2456,22 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
         return true;
     }
 
+    void setForceHideNonSystemOverlayWindowIfNeeded(boolean forceHide) {
+        if (mOwnerCanAddInternalSystemWindow
+                || (!isSystemAlertWindowType(mAttrs.type) && mAttrs.type != TYPE_TOAST)) {
+            return;
+        }
+        if (mForceHideNonSystemOverlayWindow == forceHide) {
+            return;
+        }
+        mForceHideNonSystemOverlayWindow = forceHide;
+        if (forceHide) {
+            hideLw(true /* doAnimation */, true /* requestAnim */);
+        } else {
+            showLw(true /* doAnimation */, true /* requestAnim */);
+        }
+    }
+
     public void setAppOpVisibilityLw(boolean state) {
         if (mAppOpVisibility != state) {
             mAppOpVisibility = state;
@@ -3330,7 +3355,7 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
             pw.println(Integer.toHexString(mSystemUiVisibility));
         }
         if (!mPolicyVisibility || !mPolicyVisibilityAfterAnim || !mAppOpVisibility
-                || isParentWindowHidden()|| mPermanentlyHidden) {
+                || isParentWindowHidden()|| mPermanentlyHidden || mForceHideNonSystemOverlayWindow) {
             pw.print(prefix); pw.print("mPolicyVisibility=");
                     pw.print(mPolicyVisibility);
                     pw.print(" mPolicyVisibilityAfterAnim=");
@@ -3338,7 +3363,9 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
                     pw.print(" mAppOpVisibility=");
                     pw.print(mAppOpVisibility);
                     pw.print(" parentHidden="); pw.print(isParentWindowHidden());
-                    pw.print(" mPermanentlyHidden="); pw.println(mPermanentlyHidden);
+                    pw.print(" mPermanentlyHidden="); pw.print(mPermanentlyHidden);
+                    pw.print(" mForceHideNonSystemOverlayWindow="); pw.println(
+                    mForceHideNonSystemOverlayWindow);
         }
         if (!mRelayoutCalled || mLayoutNeeded) {
             pw.print(prefix); pw.print("mRelayoutCalled="); pw.print(mRelayoutCalled);
@@ -3593,6 +3620,17 @@ class WindowState extends WindowContainer<WindowState> implements WindowManagerP
                 && (mAttrs.privateFlags & PRIVATE_FLAG_LAYOUT_CHILD_WINDOW_IN_PARENT_FRAME) != 0;
     }
 
+    /**
+     * Returns true if any window added by an application process that if of type
+     * {@link android.view.WindowManager.LayoutParams#TYPE_TOAST} or that requires that requires
+     * {@link android.app.AppOpsManager#OP_SYSTEM_ALERT_WINDOW} permission should be hidden when
+     * this window is visible.
+     */
+    boolean hideNonSystemOverlayWindowsWhenVisible() {
+        return (mAttrs.privateFlags & PRIVATE_FLAG_HIDE_NON_SYSTEM_OVERLAY_WINDOWS) != 0
+                && mSession.mCanHideNonSystemOverlayWindows;
+    }
+
     /** Returns the parent window if this is a child of another window, else null. */
     WindowState getParentWindow() {
         // NOTE: We are not calling getParent() directly as the WindowState might be a child of a
diff --git a/services/core/java/com/android/server/wm/WindowSurfaceController.java b/services/core/java/com/android/server/wm/WindowSurfaceController.java
index 27927e6c0693..1728cfbb6ef0 100644
--- a/services/core/java/com/android/server/wm/WindowSurfaceController.java
+++ b/services/core/java/com/android/server/wm/WindowSurfaceController.java
@@ -24,10 +24,8 @@ import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_SURFACE_TRACE
 import static com.android.server.wm.WindowManagerDebugConfig.DEBUG_VISIBILITY;
 import static com.android.server.wm.WindowManagerDebugConfig.TAG_WITH_CLASS_NAME;
 import static com.android.server.wm.WindowManagerDebugConfig.TAG_WM;
-import static android.view.Surface.SCALING_MODE_FREEZE;
 import static android.view.Surface.SCALING_MODE_SCALE_TO_WINDOW;
 
-import android.graphics.PixelFormat;
 import android.graphics.Point;
 import android.graphics.PointF;
 import android.graphics.Rect;
@@ -514,6 +512,8 @@ class WindowSurfaceController {
     void setShown(boolean surfaceShown) {
         mSurfaceShown = surfaceShown;
 
+        mService.updateNonSystemOverlayWindowsVisibilityIfNeeded(mAnimator.mWin, surfaceShown);
+
         if (mWindowSession != null) {
             mWindowSession.onWindowSurfaceVisibilityChanged(this, mSurfaceShown, mWindowType);
         }