Fix an IME regression for <webview> due to missing IPC message param

content/browser/browser_plugin/browser_plugin_guest.cc

 // Copyright (c) 2012 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.
 
 #include "content/browser/browser_plugin/browser_plugin_guest.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 
@@ skipping 894 matching lines @@
 void BrowserPluginGuest::OnImeCommitText(
     int browser_plugin_instance_id,
     const base::string16& text,
     const std::vector<blink::WebCompositionUnderline>& underlines,
     const gfx::Range& replacement_range,
     int relative_cursor_pos) {
   Send(new InputMsg_ImeCommitText(routing_id(), text, underlines,
                                   replacement_range, relative_cursor_pos));
 }
 
-void BrowserPluginGuest::OnImeFinishComposingText(bool keep_selection) {
+void BrowserPluginGuest::OnImeFinishComposingText(int instance_id,
+                                                  bool keep_selection) {

[wjmaclean, 2017/05/18 15:13:05]

Where is the new parameter getting used?

[EhsanK, 2017/05/18 15:21:38]

Before getting here I suppose:
https://cs.chromium.org/chromium/src/content/browser/browser_plugin/browser_p...

This IPC comes from the embedder and we need the instance ID to properly route
it.

[wjmaclean, 2017/05/18 15:37:17]

I don't understand. You added a parameter to a function, and no code seems to
use the parameter.

[EhsanK, 2017/05/18 17:44:29]

As we spoke offline, I added a DCHECK as well as some comments in the header
file for the IPC. Just to answer the question in the CL: this is a by-product of
using IPC macros for defining handlers and |browser_plugin_instance_id| being
the first param in the IPC. So we have to do it this way unfortunately. Also,
the actual value is used in the BrowserPluginMessageFilter to find this
BrowserPluginGuest.

   Send(new InputMsg_ImeFinishComposingText(routing_id(), keep_selection));
 }
 
 void BrowserPluginGuest::OnExtendSelectionAndDelete(
     int browser_plugin_instance_id,
     int before,
     int after) {
   RenderFrameHostImpl* rfh = static_cast<RenderFrameHostImpl*>(
       web_contents()->GetFocusedFrame());
   if (rfh)
@@ skipping 135 matching lines @@
           range, character_bounds);
 }
 #endif
 
 void BrowserPluginGuest::SetContextMenuPosition(const gfx::Point& position) {
   if (delegate_)
     delegate_->SetContextMenuPosition(position);
 }
 
 }  // namespace content