Mozart: Add ViewInspector contracts for hit testing.

mojo/services/ui/views/interfaces/view_associates.mojom

 // Copyright 2015 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.
 
 [DartPackage="mojo_services"]
 module mojo.ui;
 
 import "mojo/public/interfaces/application/service_provider.mojom";
+import "mojo/services/gfx/composition/interfaces/scene_token.mojom";
 import "mojo/services/ui/views/interfaces/views.mojom";
 import "mojo/services/ui/views/interfaces/view_trees.mojom";
 
 // View associates are trusted components that are attached to a view manager
 // instance with the purpose of offering additional services to views and
 // view trees registered beyond the basic operations performed by the
 // view manager itself.  Associates may be used to implement input,
 // accessibility, editing, and other capabilities.
 //
 // Associates are coupled to a view manager instance for the entire life
@@ skipping 49 matching lines @@
   array<string>? view_service_names;
 
   // The names of view tree services offered by the associate.
   // May be null if none.
   array<string>? view_tree_service_names;
 };
 
 // Provides a view associate with the ability to inspect and perform operations
 // on the contents of views and view trees.
 interface ViewInspector {
+  // Provides an interface which can be used to perform hit tests on the
+  // contents of the view tree's scene graph.
+  //
+  // The |hit_tester| will be closed if the view tree is not attached to a
+  // renderer, when it is reattached to a different renderer, or when the
+  // view tree is destroyed.
+  //
+  // The callback will be invoked the hit tester is invalidated.
+  // If |renderer_changed| is true, the client should call |GetHitTester|
+  // again to obtain a new one.  Otherwise it should assume that the view
+  // tree has become unavailable (so no hit tester is available).
+  GetHitTester(ViewTreeToken view_tree_token,
+      mojo.gfx.composition.HitTester& hit_tester) =>
+      (bool renderer_changed);
 
+  // Given an array of scene tokens, produces an array of view tokens
+  // of equal size containing the view to which the scene belongs or null
+  // if the scene token does not belong to any view.
+  //
+  // It is safe to cache the results of this operation because a scene will
+  // only ever be associated with at most one view although a view may
+  // create several scenes during its lifetime.
+  ResolveScenes(array<mojo.gfx.composition.SceneToken> scene_tokens) =>
+      (array<ViewToken?> view_tokens);
 };