IME for Mus: Fix InputMethodMusTest.DispatchKeyEvent's deadlock.

services/ui/ime/ime_server_impl.cc

 // Copyright 2016 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 "services/ui/ime/ime_server_impl.h"
 
 #include "services/catalog/public/interfaces/constants.mojom.h"
 #include "services/service_manager/public/cpp/connector.h"
 #include "services/ui/ime/ime_registrar_impl.h"
 
@@ skipping 17 matching lines @@
         "ime:ime_driver", base::Bind(&IMEServerImpl::OnGotCatalogEntries,
                                      base::Unretained(this)));
   }
 }
 
 void IMEServerImpl::AddBinding(mojom::IMEServerRequest request) {
   bindings_.AddBinding(this, std::move(request));
 }
 
 void IMEServerImpl::OnDriverChanged(mojom::IMEDriverPtr driver) {
+  // TODO(moshayedi): crbug.com/669681. Handle switching drivers properly. For
+  // now we only register the first driver to avoid clients of the previous
+  // driver from hanging.
+  if (driver_)
+    return;
+
   // TODO(moshayedi): crbug.com/664267. Make sure this is the driver we
   // requested at OnGotCatalogEntries().
   driver_ = std::move(driver);
 
   while (!pending_requests_.empty()) {
     driver_->StartSession(current_id_++,
                           std::move(pending_requests_.front().first),
                           std::move(pending_requests_.front().second));
     pending_requests_.pop();
   }
@@ skipping 18 matching lines @@
 void IMEServerImpl::OnGotCatalogEntries(
     std::vector<catalog::mojom::EntryPtr> entries) {
   // TODO(moshayedi): crbug.com/662157. Decide what to do when number of
   // available IME drivers isn't exactly one.
   if (entries.size() == 0)
     return;
   connector_->Connect((*entries.begin())->name);
 }
 
 }  // namespace ui