Accessibility fix for ShellRoot

Ensure ShellRoot layers are ordered correctly with other windows in the
system. This means placing the Shell Root layers z ordered based on the
window type

Bug: 177864415
Test: adb shell dumpsys accessibility
Change-Id: Iee982e9f17b496d413d4733f0a99997f81cee527
Merged-In: Iee982e9f17b496d413d4733f0a99997f81cee527

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

@@ -1542,6 +1542,52 @@ final class AccessibilityController {
             mEmbeddedDisplayIdList.add(displayId);
         }
 
+        boolean shellRootIsAbove(WindowState windowState, ShellRoot shellRoot) {
+            int wsLayer = mService.mPolicy.getWindowLayerLw(windowState);
+            int shellLayer = mService.mPolicy.getWindowLayerFromTypeLw(shellRoot.getWindowType(),
+                    true);
+            return shellLayer >= wsLayer;
+        }
+
+        int addShellRootsIfAbove(WindowState windowState, ArrayList<ShellRoot> shellRoots,
+                int shellRootIndex, List<WindowInfo> windows, Set<IBinder> addedWindows,
+                Region unaccountedSpace, boolean focusedWindowAdded) {
+            while (shellRootIndex < shellRoots.size()
+                    && shellRootIsAbove(windowState, shellRoots.get(shellRootIndex))) {
+                ShellRoot shellRoot = shellRoots.get(shellRootIndex);
+                shellRootIndex++;
+                final WindowInfo info = shellRoot.getWindowInfo();
+                if (info == null) {
+                    continue;
+                }
+
+                info.layer = addedWindows.size();
+                windows.add(info);
+                addedWindows.add(info.token);
+                unaccountedSpace.op(info.regionInScreen, unaccountedSpace,
+                        Region.Op.REVERSE_DIFFERENCE);
+                if (unaccountedSpace.isEmpty() && focusedWindowAdded) {
+                    break;
+                }
+            }
+            return shellRootIndex;
+        }
+
+        private ArrayList<ShellRoot> getSortedShellRoots(
+                SparseArray<ShellRoot> originalShellRoots) {
+            ArrayList<ShellRoot> sortedShellRoots = new ArrayList<>(originalShellRoots.size());
+            for (int i = originalShellRoots.size() - 1; i >= 0; --i) {
+                sortedShellRoots.add(originalShellRoots.valueAt(i));
+            }
+
+            sortedShellRoots.sort((left, right) ->
+                    mService.mPolicy.getWindowLayerFromTypeLw(right.getWindowType(), true)
+                            - mService.mPolicy.getWindowLayerFromTypeLw(left.getWindowType(),
+                            true));
+
+            return sortedShellRoots;
+        }
+
         /**
          * Check if windows have changed, and send them to the accessibility subsystem if they have.
          *
@@ -1601,9 +1647,22 @@ final class AccessibilityController {
                 final int visibleWindowCount = visibleWindows.size();
                 HashSet<Integer> skipRemainingWindowsForTasks = new HashSet<>();
 
+                ArrayList<ShellRoot> shellRoots = getSortedShellRoots(dc.mShellRoots);
+
                 // Iterate until we figure out what is touchable for the entire screen.
+                int shellRootIndex = 0;
                 for (int i = visibleWindowCount - 1; i >= 0; i--) {
                     final WindowState windowState = visibleWindows.valueAt(i);
+                    int prevShellRootIndex = shellRootIndex;
+                    shellRootIndex = addShellRootsIfAbove(windowState, shellRoots, shellRootIndex,
+                            windows, addedWindows, unaccountedSpace, focusedWindowAdded);
+
+                    // If a Shell Root was added, it could have accounted for all the space already.
+                    if (shellRootIndex > prevShellRootIndex && unaccountedSpace.isEmpty()
+                            && focusedWindowAdded) {
+                        break;
+                    }
+
                     final Region regionInScreen = new Region();
                     computeWindowRegionInScreen(windowState, regionInScreen);
 
@@ -1627,16 +1686,6 @@ final class AccessibilityController {
                     }
                 }
 
-                for (int i = dc.mShellRoots.size() - 1; i >= 0; --i) {
-                    final WindowInfo info = dc.mShellRoots.valueAt(i).getWindowInfo();
-                    if (info == null) {
-                        continue;
-                    }
-                    info.layer = addedWindows.size();
-                    windows.add(info);
-                    addedWindows.add(info.token);
-                }
-
                 // Remove child/parent references to windows that were not added.
                 final int windowCount = windows.size();
                 for (int i = 0; i < windowCount; i++) {

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

@@ -50,6 +50,7 @@ public class ShellRoot {
     private SurfaceControl mSurfaceControl = null;
     private IWindow mAccessibilityWindow;
     private IBinder.DeathRecipient mAccessibilityWindowDeath;
+    private int mWindowType;
 
     ShellRoot(@NonNull IWindow client, @NonNull DisplayContent dc,
             @WindowManager.ShellRootLayer final int shellRootLayer) {
@@ -64,19 +65,18 @@ public class ShellRoot {
             return;
         }
         mClient = client;
-        int windowType;
         switch (shellRootLayer) {
             case SHELL_ROOT_LAYER_DIVIDER:
-                windowType = TYPE_DOCK_DIVIDER;
+                mWindowType = TYPE_DOCK_DIVIDER;
                 break;
             case SHELL_ROOT_LAYER_PIP:
-                windowType = TYPE_APPLICATION_OVERLAY;
+                mWindowType = TYPE_APPLICATION_OVERLAY;
                 break;
             default:
                 throw new IllegalArgumentException(shellRootLayer
                         + " is not an acceptable shell root layer.");
         }
-        mToken = new WindowToken.Builder(dc.mWmService, client.asBinder(), windowType)
+        mToken = new WindowToken.Builder(dc.mWmService, client.asBinder(), mWindowType)
                 .setDisplayContent(dc)
                 .setPersistOnEmpty(true)
                 .setOwnerCanManageAppTokens(true)
@@ -89,6 +89,10 @@ public class ShellRoot {
         mToken.getPendingTransaction().show(mSurfaceControl);
     }
 
+    int getWindowType() {
+        return mWindowType;
+    }
+
     void clear() {
         if (mClient != null) {
             mClient.asBinder().unlinkToDeath(mDeathRecipient, 0);