Extend the geometry APIs.

mojo/services/geometry/cpp/geometry_util.cc

+// Copyright 2014 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 <string.h>
+#include "mojo/services/geometry/cpp/geometry_util.h"
+
+namespace mojo {
+
+static const float kIdentityMatrix[]{
+    1.f, 0.f, 0.f, 0.f,  // comments to prevent
+    0.f, 1.f, 0.f, 0.f,  // auto formatter reflow
+    0.f, 0.f, 1.f, 0.f,  //
+    0.f, 0.f, 0.f, 1.f};
+
+void SetIdentityTransform(Transform* transform) {
+  transform->matrix.resize(16u);
+  memcpy(transform->matrix.data(), kIdentityMatrix, sizeof(kIdentityMatrix));
+}
+
+void SetTranslationTransform(Transform* transform, float x, float y, float z) {
+  SetIdentityTransform(transform);
+  transform->matrix[3] = x;
+  transform->matrix[7] = y;
+  transform->matrix[11] = z;
+}
+
+}  // namespace mojo