AndroidOverlay implementation using Dialog.

ui/android/java/src/org/chromium/ui/base/WindowAndroid.java

Index: ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
diff --git a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
index d9771f74edd7707bc3043936bc23f221dfcc358f..962e610524218aac6b71d81020190f55396a2974 100644
--- a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
@@ -16,11 +16,13 @@ import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.os.Build;
 import android.os.Bundle;
+import android.os.IBinder;
 import android.os.Process;
 import android.util.Log;
 import android.util.SparseArray;
 import android.view.View;
 import android.view.ViewGroup;
+import android.view.Window;
 import android.view.accessibility.AccessibilityManager;
 
 import org.chromium.base.ApiCompatibilityUtils;
@@ -726,6 +728,20 @@ public class WindowAndroid {
     }
 
     /**
+     * Return the current window token, or null.
+     */
+    @CalledByNative
+    private IBinder getWindowToken() {
+        Activity activity = activityFromContext(mContextRef.get());
+        if (activity == null) return null;
+        Window window = activity.getWindow();
+        if (window == null) return null;
+        View decorView = window.peekDecorView();
+        if (decorView == null) return null;
+        return decorView.getWindowToken();
+    }
+
+    /**
      * Update whether the placeholder is 'drawn' based on whether an animation is running
      * or touch exploration is enabled - if either of those are true, we call
      * setWillNotDraw(false) to ensure that the animation is drawn over the SurfaceView,