[WIP][Ozone] Support external touchscreens

ui/ozone/platform/dri/display_manager.cc

Index: ui/ozone/platform/dri/display_manager.cc
diff --git a/ui/ozone/platform/dri/display_manager.cc b/ui/ozone/platform/dri/display_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..aadf0c55afc2ca12d91684267b9eeaa7a87ed245
--- /dev/null
+++ b/ui/ozone/platform/dri/display_manager.cc
@@ -0,0 +1,42 @@
+// 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 "ui/ozone/platform/dri/display_manager.h"
+
+#include "base/logging.h"
+#include "ui/display/types/display_snapshot.h"
+
+namespace ui {
+
+DisplayManager::DisplayManager() {
+}
+
+DisplayManager::~DisplayManager() {
+}
+
+void DisplayManager::RegisterDisplay(DisplaySnapshot* display) {
+  std::pair<DisplayMap::iterator, bool> result = display_map_.insert(
+      std::pair<int64_t, DisplaySnapshot*>(display->display_id(), display));
+  DCHECK(result.second) << "Display " << display->display_id()
+                        << " already added.";
+}
+
+void DisplayManager::UnregisterDisplay(DisplaySnapshot* display) {
+  DisplayMap::iterator it = display_map_.find(display->display_id());
+  if (it != display_map_.end())
+    display_map_.erase(it);
+  else
+    NOTREACHED() << "Attempting to remove non-existing display "
+                 << display->display_id();
+}
+
+DisplaySnapshot* DisplayManager::GetDisplay(int64_t display) {
+  DisplayMap::iterator it = display_map_.find(display);
+  if (it == display_map_.end())
+    return nullptr;
+
+  return it->second;
+}
+
+}  // namespace ui