Add a full screen virtual keyboard to virtual keyboard root window

ui/keyboard/keyboard_util.cc

Index: ui/keyboard/keyboard_util.cc
diff --git a/ui/keyboard/keyboard_util.cc b/ui/keyboard/keyboard_util.cc
index 96d8385a05fddfe53103522b90eb99c21a340ae1..670a758051a73c24ff72b61728fd47eb45b289d8 100644
--- a/ui/keyboard/keyboard_util.cc
+++ b/ui/keyboard/keyboard_util.cc
@@ -42,9 +42,12 @@ namespace keyboard {
 bool IsKeyboardEnabled() {
   return CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kEnableVirtualKeyboard) ||
-          CommandLine::ForCurrentProcess()->HasSwitch(
-              switches::kKeyboardUsabilityTest);
+          IsKeyboardUsabilityExperimentEnabled();
+}
 
+bool IsKeyboardUsabilityExperimentEnabled() {
+  return CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kKeyboardUsabilityExperiment);
 }
 
 bool InsertText(const base::string16& text, aura::Window* root_window) {