Introduce a secondary map for enabling plznavigate

android_webview/browser/aw_contents_io_thread_client.h

Index: android_webview/browser/aw_contents_io_thread_client.h
diff --git a/android_webview/browser/aw_contents_io_thread_client.h b/android_webview/browser/aw_contents_io_thread_client.h
index e9a0bf3411514f0f28d08fdd5223375034ab3b9f..3eb8ae637ce8d96b840b46eb5f83b2a3e10020f0 100644
--- a/android_webview/browser/aw_contents_io_thread_client.h
+++ b/android_webview/browser/aw_contents_io_thread_client.h
@@ -63,6 +63,11 @@ class AwContentsIoThreadClient {
   static std::unique_ptr<AwContentsIoThreadClient> FromID(int render_process_id,
                                                           int render_frame_id);
 
+  // This map is useful when browser side navigations are enabled as
+  // render_frame_ids will not be valid anymore for some of the navigations.
+  static std::unique_ptr<AwContentsIoThreadClient> FromID(
+      int frame_tree_node_id);
+
   // Returns the global thread client for service worker related callbacks.
   // An empty scoped_ptr is a valid return value.
   static std::unique_ptr<AwContentsIoThreadClient>