Enable Config::MUS to use classic IME instead of servicified IME.

ash/display/window_tree_host_manager.cc

Index: ash/display/window_tree_host_manager.cc
diff --git a/ash/display/window_tree_host_manager.cc b/ash/display/window_tree_host_manager.cc
index bce98e78e056894aeb9fad3559837a808bcb5f3d..073be1f74457c2d1573a7bfeefb9fffca100bf14 100644
--- a/ash/display/window_tree_host_manager.cc
+++ b/ash/display/window_tree_host_manager.cc
@@ -823,21 +823,18 @@ AshWindowTreeHost* WindowTreeHostManager::AddWindowTreeHostForDisplay(
   AshWindowTreeHost* ash_host =
       AshWindowTreeHost::Create(params_with_bounds).release();
   aura::WindowTreeHost* host = ash_host->AsWindowTreeHost();
-  // TODO: Config::MUS should not install an InputMethod.
-  // http://crbug.com/706913
-  if (!host->has_input_method()) {
-    if (!input_method_) {  // Singleton input method instance for Ash.
-      input_method_ = ui::CreateInputMethod(this, host->GetAcceleratedWidget());
-      // Makes sure the input method is focused by default when created, because
-      // Ash uses singleton InputMethod and it won't call OnFocus/OnBlur when
-      // the active window changed.
-      input_method_->OnFocus();
-      input_method_event_handler_.reset(
-          new InputMethodEventHandler(input_method_.get()));
-    }
-    host->SetSharedInputMethod(input_method_.get());
-    ash_host->set_input_method_handler(input_method_event_handler_.get());
+  DCHECK(!host->has_input_method());

[sky, 2017/05/03 15:25:27]

The plan is to use this code for both mash and mus. For the mash case IME will
be hosted by chrome, for the mus case we want what you have here. So, doesn't
this code need to know the ash::Config so that it conditionally set the
InputMethod?

[Hadi, 2017/05/03 19:35:42]

Done.

+  if (!input_method_) {  // Singleton input method instance for Ash.
+    input_method_ = ui::CreateInputMethod(this, host->GetAcceleratedWidget());
+    // Makes sure the input method is focused by default when created, because
+    // Ash uses singleton InputMethod and it won't call OnFocus/OnBlur when
+    // the active window changed.
+    input_method_->OnFocus();
+    input_method_event_handler_.reset(
+        new InputMethodEventHandler(input_method_.get()));
   }
+  host->SetSharedInputMethod(input_method_.get());
+  ash_host->set_input_method_handler(input_method_event_handler_.get());
 
   host->window()->SetName(base::StringPrintf(
       "%sRootWindow-%d", params_with_bounds.offscreen ? "Offscreen" : "",