AndroidOverlay implementation using Dialog.

content/common/frame_messages.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // IPC messages for interacting with frames.
 // Multiply-included message file, hence no include guard.
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 871 matching lines @@
 //
 // If match rects are already cached on the browser side, |current_version|
 // should be the version number from the FrameHostMsg_FindMatchRects_Reply
 // they came in, so the renderer can tell if it needs to send updated rects.
 // Otherwise just pass -1 to always receive the list of rects.
 //
 // There must be an active search string (it is probably most useful to call
 // 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_ROUTED2(FrameMsg_SetOverlayRoutingToken,
+                    uint64_t /* high */,

[dcheng, 2017/04/03 19:12:40]

Why not just send the base::UnguessableToken directly?

[liberato (no reviews please), 2017/04/04 17:49:29]

because i forgot that it had paramtraits already.  thanks!

+                    uint64_t /* low */)
 #endif
 
 #if BUILDFLAG(USE_EXTERNAL_POPUP_MENU)
 #if defined(OS_MACOSX)
 IPC_MESSAGE_ROUTED1(FrameMsg_SelectPopupMenuItem,
                     int /* selected index, -1 means no selection */)
 #else
 IPC_MESSAGE_ROUTED2(FrameMsg_SelectPopupMenuItems,
                     bool /* user canceled the popup */,
                     std::vector<int> /* selected indices */)
@@ skipping 737 matching lines @@
                     std::vector<gfx::RectF> /* rects */,
                     gfx::RectF /* active_rect */)
 
 // Response to FrameMsg_GetNearestFindResult. |distance| is the distance to the
 // nearest find result in the sending frame.
 IPC_MESSAGE_ROUTED2(FrameHostMsg_GetNearestFindResult_Reply,
                     int /* nfr_request_id */,
                     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
 // independent FrameMsg, then ifdefs for platform specific FrameMsg, then
 // platform independent FrameHostMsg, then ifdefs for platform specific
 // FrameHostMsg.