mus: Add PointerWatcher for passively observing mouse and touch events

ash/pointer_watcher_delegate_aura.cc

Index: ash/pointer_watcher_delegate_aura.cc
diff --git a/ash/pointer_watcher_delegate_aura.cc b/ash/pointer_watcher_delegate_aura.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f2050bdd90143227f5baa1bd106d90759db2f8a1
--- /dev/null
+++ b/ash/pointer_watcher_delegate_aura.cc
@@ -0,0 +1,44 @@
+// Copyright 2016 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/pointer_watcher_delegate_aura.h"
+
+#include "ash/shell.h"
+#include "ui/events/event.h"
+#include "ui/events/event_constants.h"
+#include "ui/views/pointer_watcher.h"
+
+namespace ash {
+
+PointerWatcherDelegateAura::PointerWatcherDelegateAura() {
+  Shell::GetInstance()->AddPreTargetHandler(this);
+}
+
+PointerWatcherDelegateAura::~PointerWatcherDelegateAura() {
+  Shell::GetInstance()->RemovePreTargetHandler(this);
+}
+
+void PointerWatcherDelegateAura::AddPointerWatcher(
+    views::PointerWatcher* watcher) {
+  pointer_watchers_.AddObserver(watcher);
+}
+
+void PointerWatcherDelegateAura::RemovePointerWatcher(
+    views::PointerWatcher* watcher) {
+  pointer_watchers_.RemoveObserver(watcher);
+}
+
+void PointerWatcherDelegateAura::OnMouseEvent(ui::MouseEvent* event) {
+  if (event->type() == ui::ET_MOUSE_PRESSED)
+    FOR_EACH_OBSERVER(views::PointerWatcher, pointer_watchers_,
+                      OnMousePressed(*event));
+}
+
+void PointerWatcherDelegateAura::OnTouchEvent(ui::TouchEvent* event) {
+  if (event->type() == ui::ET_TOUCH_PRESSED)
+    FOR_EACH_OBSERVER(views::PointerWatcher, pointer_watchers_,
+                      OnTouchPressed(*event));
+}
+
+}  // namespace ash