Implement GetTextFromRange(), GetTextRange() and GetSelectionRange() for ArcImeService.

components/arc/ime/arc_ime_struct_traits.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 "components/arc/ime/arc_ime_struct_traits.h"
+
+namespace mojo {
+
+bool StructTraits<arc::mojom::CursorRectDataView, gfx::Rect>::Read(
+    arc::mojom::CursorRectDataView data,
+    gfx::Rect* out) {
+  out->set_x(data.left());
+  out->set_y(data.top());
+  out->set_width(data.right() - out->x());
+  out->set_height(data.bottom() - out->y());
+  return true;
+}
+
+bool StructTraits<arc::mojom::TextRangeDataView, gfx::Range>::Read(
+    arc::mojom::TextRangeDataView data,
+    gfx::Range* out) {
+  out->set_start(data.start());
+  out->set_end(data.end());
+  return true;
+}
+
+}  // namespace mojo