AndroidOverlay implementation using Dialog.

content/common/frame_messages.h

Index: content/common/frame_messages.h
diff --git a/content/common/frame_messages.h b/content/common/frame_messages.h
index aebe97582a5bcbc7bf8ec4bc6a735c80c8dd4bfa..f0a05f0baf0fad48433a572253d9e7893a4ccc6e 100644
--- a/content/common/frame_messages.h
+++ b/content/common/frame_messages.h
@@ -896,6 +896,10 @@ IPC_MESSAGE_ROUTED3(FrameMsg_ActivateNearestFindResult,
 // this immediately after a FrameHostMsg_Find_Reply message arrives with
 // final_update set to true).
 IPC_MESSAGE_ROUTED1(FrameMsg_FindMatchRects, int /* current_version */)
+
+// Notify the renderer of our overlay routing token.
+IPC_MESSAGE_ROUTED1(FrameMsg_SetOverlayRoutingToken,
+                    base::UnguessableToken /* routing_token */)
 #endif
 
 #if BUILDFLAG(USE_EXTERNAL_POPUP_MENU)
@@ -1657,6 +1661,10 @@ IPC_MESSAGE_ROUTED2(FrameHostMsg_GetNearestFindResult_Reply,
                     float /* distance */)
 
 IPC_MESSAGE_ROUTED0(FrameHostMsg_NavigationHandledByEmbedder)
+
+// Request that the host send its overlay routing token for this render frame
+// via SetOverlayRoutingToken.
+IPC_MESSAGE_ROUTED0(FrameHostMsg_RequestOverlayRoutingToken)
 #endif
 
 // Adding a new message? Stick to the sort order above: first platform