Add a WM API to query the touch region for the input method window

This is needed by VR to handle keyboards that display a window larger
than the interactable region

Bug: 62194867
Test: Manually with prints
Change-Id: I7288956ed8da8d24e7c46ffa8f27461f7abbca5e

core/java/android/view/IWindowManager.aidl

@@ -29,6 +29,7 @@ import android.graphics.Bitmap;
 import android.graphics.GraphicBuffer;
 import android.graphics.Point;
 import android.graphics.Rect;
+import android.graphics.Region;
 import android.os.Bundle;
 import android.os.IRemoteCallback;
 import android.os.ParcelFileDescriptor;
@@ -377,4 +378,9 @@ interface IWindowManager
      * associated with that InputConsumer.
      */
     boolean destroyInputConsumer(String name);
+
+    /**
+     * Return the touch region for the current IME window, or an empty region if there is none.
+     */
+    Region getCurrentImeTouchRegion();
 }

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

@@ -6168,6 +6168,17 @@ public class WindowManagerService extends IWindowManager.Stub
         }
     }
 
+    @Override
+    public Region getCurrentImeTouchRegion() {
+        synchronized (mWindowMap) {
+            final Region r = new Region();
+            if (mInputMethodWindow != null) {
+                mInputMethodWindow.getTouchableRegion(r);
+            }
+            return r;
+        }
+    }
+
     @Override
     public boolean hasNavigationBar() {
         return mPolicy.hasNavigationBar();