[mus+ash] Implements hit-test client in Aura

ui/aura/mus/hit_test_data_provider_mus.cc

+// 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/hit_test_data_provider_mus.h"
+
+#include "base/containers/adapters.h"
+#include "ui/aura/mus/window_port_mus.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_targeter.h"
+
+namespace aura {
+
+HitTestDataProviderMus::HitTestDataProviderMus(aura::Window* window)
+    : window_(window) {}
+
+HitTestDataProviderMus::~HitTestDataProviderMus() {}
+
+std::unique_ptr<viz::HitTestDataProvider::HitTestRegionList>
+HitTestDataProviderMus::GetHitTestData() {
+  auto hit_test_region_list = base::MakeUnique<HitTestRegionList>();
+  GetHitTestDataRecursively(window_, hit_test_region_list.get());
+  return hit_test_region_list;
+}
+
+void HitTestDataProviderMus::GetHitTestDataRecursively(
+    aura::Window* window,
+    HitTestRegionList* hit_test_region_list) {
+  WindowTargeter* targeter =
+      static_cast<WindowTargeter*>(window->GetEventTargeter());
+
+  // Walk the children in Z-order (reversed order of children()) to produce
+  // the hit-test data. Each child's hit test data is added before the hit-test
+  // data from the child's descendants because the child could clip its
+  // descendants for the purpose of event handling.
+  for (aura::Window* child : base::Reversed(window->children())) {
+    gfx::Rect rect_mouse;
+    gfx::Rect rect_touch;
+    if (targeter &&
+        targeter->GetHitTestRects(child, &rect_mouse, &rect_touch)) {
+      const bool touch_and_mouse_are_same = rect_mouse == rect_touch;
+      const WindowPortMus* window_port = WindowPortMus::Get(child);
+      viz::DisplayHitTestRegion hit_test_region = {window_port->frame_sink_id(),
+                                                   window_port->server_id(), 0};
+      if (!rect_mouse.IsEmpty()) {
+        hit_test_region.flags = touch_and_mouse_are_same ? 0x03 : 0x01;
+        hit_test_region.rect = rect_mouse;
+        hit_test_region_list->push_back(hit_test_region);
+      }
+      if (!touch_and_mouse_are_same && !rect_touch.IsEmpty()) {
+        hit_test_region.flags = 0x02;
+        hit_test_region.rect = rect_touch;
+        hit_test_region_list->push_back(hit_test_region);
+      }
+    }
+    GetHitTestDataRecursively(child, hit_test_region_list);
+  }
+}
+
+}  // namespace aura