Add a full screen virtual keyboard to virtual keyboard root window

ash/keyboard_controller_proxy_stub.cc

Index: ash/keyboard_controller_proxy_stub.cc
diff --git a/ash/keyboard_controller_proxy_stub.cc b/ash/keyboard_controller_proxy_stub.cc
index caaa3dd8a2e1365201b459722936261f77a61cdc..1236d203cdcd2ee92ea86eabf43dd9ea15e4fb41 100644
--- a/ash/keyboard_controller_proxy_stub.cc
+++ b/ash/keyboard_controller_proxy_stub.cc
@@ -5,6 +5,7 @@
 #include "ash/keyboard_controller_proxy_stub.h"
 
 #include "ash/shell.h"
+#include "ui/aura/window.h"
 #include "ui/views/corewm/input_method_event_filter.h"
 
 using namespace content;
@@ -17,6 +18,12 @@ KeyboardControllerProxyStub::KeyboardControllerProxyStub() {
 KeyboardControllerProxyStub::~KeyboardControllerProxyStub() {
 }
 
+aura::Window* KeyboardControllerProxyStub::GetKeyboardWindow() {
+  aura::Window* window = new aura::Window(&delegate_);
+  window->Init(ui::LAYER_NOT_DRAWN);
+  return window;
+}
+
 BrowserContext* KeyboardControllerProxyStub::GetBrowserContext() {
   return Shell::GetInstance()->browser_context();
 }