Mozart: Add helpers for building view associates.

mojo/ui/associates/resolved_hits.h

Index: mojo/ui/associates/resolved_hits.h
diff --git a/mojo/ui/associates/resolved_hits.h b/mojo/ui/associates/resolved_hits.h
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+++ b/mojo/ui/associates/resolved_hits.h
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+// 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.
+
+#ifndef MOJO_UI_ASSOCIATES_RESOLVED_HIT_TEST_H_
+#define MOJO_UI_ASSOCIATES_RESOLVED_HIT_TEST_H_
+
+#include <iosfwd>
+#include <memory>
+#include <unordered_map>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "mojo/services/ui/views/interfaces/view_associates.mojom.h"
+
+namespace mojo {
+namespace ui {
+
+using SceneTokenValueToViewTokenMap =
+    std::unordered_map<uint32_t, mojo::ui::ViewTokenPtr>;
+
+// A hit test result combined with a map explaining how scenes are mapped
+// to views.
+class ResolvedHits {
+ public:
+  ResolvedHits(mojo::gfx::composition::HitTestResultPtr result);
+  ~ResolvedHits();
+
+  // The hit test result, not null unless |TakeResult| was called.
+  const mojo::gfx::composition::HitTestResult* result() const {
+    return result_.get();
+  }
+  mojo::gfx::composition::HitTestResultPtr TakeResult() {
+    return result_.Pass();
+  }
+
+  // A map from scene token value to view token containing all scenes which
+  // could be resolved.
+  const SceneTokenValueToViewTokenMap& map() const { return map_; }
+
+  // Adds a mapping for the specified scene token value to a view token.
+  void AddMapping(uint32_t scene_token_value,
+                  mojo::ui::ViewTokenPtr view_token);
+
+ private:
+  mojo::gfx::composition::HitTestResultPtr result_;
+  SceneTokenValueToViewTokenMap map_;
+
+  DISALLOW_COPY_AND_ASSIGN(ResolvedHits);
+};
+
+// Provides a resolved description of the hit test results, or null if the
+// hit test could not be performed at all.
+// TODO(jeffbrown): Would prefer to use |std::unique_ptr| here but it doesn't
+// play nice with base::Callback right now.
+using ResolvedHitsCallback = base::Callback<void(scoped_ptr<ResolvedHits>)>;
+
+std::ostream& operator<<(std::ostream& os, const mojo::ui::ResolvedHits& value);
+std::ostream& operator<<(std::ostream& os, const mojo::ui::ResolvedHits* value);
+
+}  // namespace ui
+}  // namespace mojo
+
+#endif  // MOJO_UI_ASSOCIATES_RESOLVED_HIT_TEST_H_