[WIP][Ozone] Support external touchscreens

ash/touch/touch_transformer_controller_ozone.cc

Index: ash/touch/touch_transformer_controller_ozone.cc
diff --git a/ash/touch/touch_transformer_controller_ozone.cc b/ash/touch/touch_transformer_controller_ozone.cc
new file mode 100644
index 0000000000000000000000000000000000000000..d0e2e9df4189075e2f90a5f9b061b16351760436
--- /dev/null
+++ b/ash/touch/touch_transformer_controller_ozone.cc
@@ -0,0 +1,47 @@
+// Copyright 2014 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 "ash/touch/touch_transformer_controller.h"
+
+#include "ash/display/display_manager.h"
+#include "ash/shell.h"
+#include "ui/events/device_data_manager.h"
+
+namespace ash {
+
+TouchTransformerController::TouchTransformerController()
+    : force_compute_mirror_mode_touch_transformer_(false) {
+  Shell::GetInstance()->display_controller()->AddObserver(this);
+}
+
+TouchTransformerController::~TouchTransformerController() {
+  Shell::GetInstance()->display_controller()->RemoveObserver(this);
+}
+
+void TouchTransformerController::UpdateTouchTransformer() const {
+  ui::DeviceDataManager* device_manager = ui::DeviceDataManager::GetInstance();
+  device_manager->ClearTouchTransformerRecord();
+
+  DisplayManager* display_manager = Shell::GetInstance()->display_manager();
+  const std::vector<gfx::Display>& displays = display_manager->displays();
+  for (size_t i = 0; i < displays.size(); ++i) {
+    DisplayInfo display = display_manager->GetDisplayInfo(displays[i].id());
+    if (display.touch_support() != gfx::Display::TOUCH_SUPPORT_AVAILABLE)
+      continue;
+
+    // On Ozone we only care about the display <-> touchscreen mapping.
+    device_manager->UpdateTouchInfoForDisplay(
+        display.id(), display.touch_device_id(), gfx::Transform());
+  }
+}
+
+void TouchTransformerController::OnDisplaysInitialized() {
+  UpdateTouchTransformer();
+}
+
+void TouchTransformerController::OnDisplayConfigurationChanged() {
+  UpdateTouchTransformer();
+}
+
+}  // namespace ash