DialogSurfaceManager implementation.

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 88f64bda1a6cb1e0746abc7bd904cc7b1bebef03..eed08f65bf245058e1baa4216c31be5cd9b98c94 100644
--- a/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
+++ b/ui/android/java/src/org/chromium/ui/base/WindowAndroid.java
@@ -17,6 +17,7 @@ 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;
@@ -715,6 +716,20 @@ public class WindowAndroid {
     }
 
     /**
+     * Return the current window token, or null.
+     */
+    @CalledByNative
+    private IBinder getWindowToken() {
+        Context context = mContextRef.get();
+        if (context == null) return null;
+        Activity activity = activityFromContext(context);
+        if (activity == null) return null;
+        View decorView = activity.getWindow().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,