Mozart: Add helpers for building view associates.

mojo/ui/associates/view_tree_hit_tester_client.cc

Index: mojo/ui/associates/view_tree_hit_tester_client.cc
diff --git a/mojo/ui/associates/view_tree_hit_tester_client.cc b/mojo/ui/associates/view_tree_hit_tester_client.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c98d059a22b1e6835167dd7a6603f15751b8f674
--- /dev/null
+++ b/mojo/ui/associates/view_tree_hit_tester_client.cc
@@ -0,0 +1,92 @@
+// 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 "mojo/ui/associates/view_tree_hit_tester_client.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+
+namespace mojo {
+namespace ui {
+
+ViewTreeHitTesterClient::ViewTreeHitTesterClient(
+    const scoped_refptr<ViewInspectorClient>& view_inspector_client,
+    mojo::ui::ViewTreeTokenPtr view_tree_token)
+    : view_inspector_client_(view_inspector_client),
+      view_tree_token_(view_tree_token.Pass()),
+      weak_factory_(this) {
+  DCHECK(view_inspector_client_);
+  DCHECK(view_tree_token_);
+
+  UpdateHitTester();
+}
+
+ViewTreeHitTesterClient::~ViewTreeHitTesterClient() {}
+
+void ViewTreeHitTesterClient::HitTest(mojo::PointPtr point,
+                                      const ResolvedHitsCallback& callback) {
+  if (!hit_tester_) {
+    callback.Run(nullptr);
+    return;
+  }
+
+  // TODO(jeffbrown): Here we are assuming that the hit test callbacks will be
+  // invoked in FIFO order.  It might be a good idea to eliminate that
+  // assumption.
+  pending_callbacks_.push(callback);
+  hit_tester_->HitTest(point.Pass(),
+                       base::Bind(&ViewTreeHitTesterClient::OnHitTestResult,
+                                  base::Unretained(this)));
+}
+
+void ViewTreeHitTesterClient::OnHitTestResult(
+    mojo::gfx::composition::HitTestResultPtr result) {
+  DCHECK(result);
+  DCHECK(!pending_callbacks_.empty());
+
+  view_inspector_client_->ResolveHits(result.Pass(),
+                                      pending_callbacks_.front());
+  pending_callbacks_.pop();
+}
+
+void ViewTreeHitTesterClient::UpdateHitTester() {
+  DCHECK(!hit_tester_);
+
+  view_inspector_client_->view_inspector()->GetHitTester(
+      view_tree_token_.Clone(), mojo::GetProxy(&hit_tester_),
+      base::Bind(&ViewTreeHitTesterClient::OnHitTesterInvalidated,
+                 weak_factory_.GetWeakPtr()));
+
+  hit_tester_.set_connection_error_handler(base::Bind(
+      &ViewTreeHitTesterClient::OnHitTesterDied, base::Unretained(this)));
+}
+
+void ViewTreeHitTesterClient::ReleaseHitTester() {
+  hit_tester_.reset();
+
+  while (!pending_callbacks_.empty()) {
+    pending_callbacks_.front().Run(nullptr);
+    pending_callbacks_.pop();
+  }
+}
+
+void ViewTreeHitTesterClient::OnHitTesterInvalidated(bool renderer_changed) {
+  ReleaseHitTester();
+
+  if (renderer_changed)
+    UpdateHitTester();
+
+  if (!hit_tester_changed_callback_.is_null())
+    hit_tester_changed_callback_.Run();
+}
+
+void ViewTreeHitTesterClient::OnHitTesterDied() {
+  ReleaseHitTester();
+
+  if (!hit_tester_changed_callback_.is_null())
+    hit_tester_changed_callback_.Run();
+}
+
+}  // namespace ui
+}  // namespace mojo