Add --keyboard-usability-test flag and always show keyboard unless manually hide

ui/keyboard/keyboard_controller.cc

 // Copyright (c) 2013 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 "ui/keyboard/keyboard_controller.h"
 
 #include "base/bind.h"
+#include "base/command_line.h"
 #include "ui/aura/layout_manager.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_delegate.h"
 #include "ui/base/cursor/cursor.h"
 #include "ui/base/hit_test.h"
 #include "ui/base/ime/input_method.h"
 #include "ui/base/ime/text_input_client.h"
 #include "ui/base/ime/text_input_type.h"
 #include "ui/gfx/path.h"
 #include "ui/gfx/rect.h"
 #include "ui/gfx/skia_util.h"
 #include "ui/keyboard/keyboard_controller_observer.h"
 #include "ui/keyboard/keyboard_controller_proxy.h"
+#include "ui/keyboard/keyboard_switches.h"
 #include "ui/keyboard/keyboard_util.h"
 
 namespace {
 
 const int kHideKeyboardDelayMs = 100;
 
 gfx::Rect KeyboardBoundsFromWindowBounds(const gfx::Rect& window_bounds) {
   const float kKeyboardHeightRatio = 0.3f;
   return gfx::Rect(
       window_bounds.x(),
@@ skipping 150 matching lines @@
 
 void KeyboardController::OnTextInputStateChanged(
     const ui::TextInputClient* client) {
   if (!container_.get())
     return;
 
   bool was_showing = keyboard_visible_;
   bool should_show = was_showing;
   ui::TextInputType type =
       client ? client->GetTextInputType() : ui::TEXT_INPUT_TYPE_NONE;
-  if (type == ui::TEXT_INPUT_TYPE_NONE) {
+  if (type == ui::TEXT_INPUT_TYPE_NONE &&
+      !CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kKeyboardUsabilityTest)) {
     should_show = false;
   } else {
     if (container_->children().empty()) {
       aura::Window* keyboard = proxy_->GetKeyboardWindow();
       keyboard->Show();
       container_->AddChild(keyboard);
       container_->layout_manager()->OnWindowResized();
     }
     proxy_->SetUpdateInputType(type);
     container_->parent()->StackChildAtTop(container_.get());
@@ skipping 38 matching lines @@
     const ui::InputMethod* input_method) {
   DCHECK_EQ(input_method_, input_method);
   input_method_ = NULL;
 }
 
 bool KeyboardController::WillHideKeyboard() const {
   return weak_factory_.HasWeakPtrs();
 }
 
 }  // namespace keyboard