mash: make Env::last_mouse_location() accurate for Mus

ui/aura/mus/mus_mouse_location_updater.cc

Index: ui/aura/mus/mus_mouse_location_updater.cc
diff --git a/ui/aura/mus/mus_mouse_location_updater.cc b/ui/aura/mus/mus_mouse_location_updater.cc
new file mode 100644
index 0000000000000000000000000000000000000000..cbf89bd620a7980583599cc32916739fda36b711
--- /dev/null
+++ b/ui/aura/mus/mus_mouse_location_updater.cc
@@ -0,0 +1,67 @@
+// Copyright 2017 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/aura/mus/mus_mouse_location_updater.h"
+
+#include "ui/aura/env.h"
+#include "ui/events/event.h"
+
+namespace aura {
+namespace {
+
+bool IsMouseEventWithLocation(const ui::Event& event) {
+  // All mouse events except exited, capture, and wheel which mus doesn't
+  // include locations for.
+  switch (event.type()) {
+    case ui::ET_MOUSE_PRESSED:
+    case ui::ET_MOUSE_DRAGGED:
+    case ui::ET_MOUSE_RELEASED:
+    case ui::ET_MOUSE_MOVED:
+    case ui::ET_MOUSE_ENTERED:
+      return true;
+    default:
+      break;
+  }
+  return false;
+}
+
+}  // namespace
+
+MusMouseLocationUpdater::MusMouseLocationUpdater() {
+  base::MessageLoop::current()->AddNestingObserver(this);
+}
+
+MusMouseLocationUpdater::~MusMouseLocationUpdater() {
+  base::MessageLoop::current()->RemoveNestingObserver(this);
+}
+
+void MusMouseLocationUpdater::OnEventProcessingStarted(const ui::Event& event) {
+  if (!IsMouseEventWithLocation(event) ||
+      Env::GetInstance()->always_use_last_mouse_location_) {
+    return;
+  }
+
+  is_processing_trigger_event_ = true;
+  Env::GetInstance()->set_last_mouse_location(
+      event.AsMouseEvent()->root_location());
+  Env::GetInstance()->get_last_mouse_location_from_mus_ = false;
+}
+
+void MusMouseLocationUpdater::OnEventProcessingFinished() {
+  UseCursorScreenPoint();
+}
+
+void MusMouseLocationUpdater::UseCursorScreenPoint() {
+  if (!is_processing_trigger_event_)
+    return;
+
+  is_processing_trigger_event_ = false;
+  Env::GetInstance()->get_last_mouse_location_from_mus_ = true;
+}
+
+void MusMouseLocationUpdater::OnBeginNestedMessageLoop() {
+  UseCursorScreenPoint();
+}
+
+}  // namespace aura