Combine the WM_CHAR with WM_KEY* for key event flow.

ui/aura/remote_window_tree_host_win.cc

Index: ui/aura/remote_window_tree_host_win.cc
diff --git a/ui/aura/remote_window_tree_host_win.cc b/ui/aura/remote_window_tree_host_win.cc
index 842598c823ffdafd851c9ebed9b692d8be36e67d..ebaf3c21e3e42f9c861da7c6603671ff62105532 100644
--- a/ui/aura/remote_window_tree_host_win.cc
+++ b/ui/aura/remote_window_tree_host_win.cc
@@ -148,6 +148,8 @@ bool RemoteWindowTreeHostWin::OnMessageReceived(const IPC::Message& message) {
     IPC_MESSAGE_HANDLER(MetroViewerHostMsg_KeyDown, OnKeyDown)
     IPC_MESSAGE_HANDLER(MetroViewerHostMsg_KeyUp, OnKeyUp)
     IPC_MESSAGE_HANDLER(MetroViewerHostMsg_Character, OnChar)
+    IPC_MESSAGE_HANDLER(MetroViewerHostMsg_CharacterForNextKeyEvent,
+                        OnCharForNextKeyEvent)
     IPC_MESSAGE_HANDLER(MetroViewerHostMsg_WindowActivated,
                         OnWindowActivated)
     IPC_MESSAGE_HANDLER(MetroViewerHostMsg_EdgeGesture, OnEdgeGesture)
@@ -369,6 +371,18 @@ void RemoteWindowTreeHostWin::OnChar(uint32 key_code,
                           scan_code, flags, true);
 }
 
+void RemoteWindowTreeHostWin::OnCharForNextKeyEvent(uint32 key_code,
+                                                    uint32 repeat_count,
+                                                    uint32 scan_code,
+                                                    uint32 flags) {
+  ui::RemoteInputMethodPrivateWin* remote_input_method_private =

[jln (very slow on Chromium), 2015/08/17 21:35:07]

It's unfortunate that none of the IPC parameters are validated on-site (in this
file) before being passes to DispatchKeyboardMessage().

Here it looks like most of them are not even used. Could you check that they are
passed as (for instance) 0 and add a comment that if they need to get used, they
should be validated carefully?

[Shu Chen, 2015/08/18 08:49:41]

Done. I've removed the unused parameters.

+      GetRemoteInputMethodPrivate();
+  if (remote_input_method_private) {
+    remote_input_method_private->OnCharForNextKeyEvent(
+        static_cast<base::char16>(key_code));
+  }
+}
+
 void RemoteWindowTreeHostWin::OnWindowActivated(bool repaint) {
   OnHostActivated();
   if (repaint && compositor())