MacViews: Implement Force Touch/Mac dictionary lookup for Textfields.

ui/views/word_lookup_client.h

+// 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 UI_VIEWS_WORD_LOOKUP_CLIENT_H_
+#define UI_VIEWS_WORD_LOOKUP_CLIENT_H_
+
+#include "ui/views/views_export.h"
+
+namespace gfx {
+struct DecoratedText;
+class Point;
+}
+
+namespace views {
+
+// An interface implemented by a view which supports word lookups.
+class VIEWS_EXPORT WordLookupClient {
+ public:
+  // Retrieves the word displayed at the given |point| along with its styling
+  // information. |point| is in the coordinate system of the view. If no word is
+  // displayed at the point, returns a nearby word. |baseline_point| should
+  // correspond to the baseline point of the leftmost glyph of the |word| in the
+  // view's coordinates. Returns false, if no word can be retrieved.
+  virtual bool GetDecoratedWordAtPoint(const gfx::Point& point,
+                                       gfx::DecoratedText* decorated_word,
+                                       gfx::Point* baseline_point) = 0;
+
+ protected:
+  virtual ~WordLookupClient() {}
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_WORD_LOOKUP_CLIENT_H_