Expose WindowAndroid from WebContents.

content/browser/web_contents/web_contents_android.cc

Index: content/browser/web_contents/web_contents_android.cc
diff --git a/content/browser/web_contents/web_contents_android.cc b/content/browser/web_contents/web_contents_android.cc
index 842b860337c64cfd48970e683a8bce5ef33d700b..a93fad88c15d0d4ce70b90c16d81ef9332fe13f6 100644
--- a/content/browser/web_contents/web_contents_android.cc
+++ b/content/browser/web_contents/web_contents_android.cc
@@ -39,6 +39,7 @@
 #include "net/android/network_library.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/android/overscroll_refresh_handler.h"
+#include "ui/android/window_android.h"
 #include "ui/gfx/android/java_bitmap.h"
 #include "ui/gfx/geometry/rect.h"
 
@@ -284,6 +285,15 @@ WebContentsAndroid::GetJavaObject() {
   return base::android::ScopedJavaLocalRef<jobject>(obj_);
 }
 
+base::android::ScopedJavaLocalRef<jobject>
+WebContentsAndroid::GetTopLevelNativeWindow(JNIEnv* env,
+                                            const JavaParamRef<jobject>& obj) {
+  ui::WindowAndroid* window_android = web_contents_->GetTopLevelNativeWindow();
+  if (!window_android)
+    return nullptr;
+  return window_android->GetJavaObject();
+}
+
 ScopedJavaLocalRef<jstring> WebContentsAndroid::GetTitle(
     JNIEnv* env,
     const JavaParamRef<jobject>& obj) const {