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

content/browser/browser_plugin/browser_plugin_guest.cc

Index: content/browser/browser_plugin/browser_plugin_guest.cc
diff --git a/content/browser/browser_plugin/browser_plugin_guest.cc b/content/browser/browser_plugin/browser_plugin_guest.cc
index 4114d6535131c6b5b97f4c115020c1b58ea88c4e..f12e85858006330fc1ae9a263f1050d421df08d7 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.cc
+++ b/content/browser/browser_plugin/browser_plugin_guest.cc
@@ -912,7 +912,8 @@ void BrowserPluginGuest::OnImeCommitText(
                                   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));
 }