Harmony: Apply the upper bound on equal-sized button widths in DialogClientView.

ui/views/test/test_layout_provider.h

+// 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.
+
+#ifndef UI_VIEWS_TEST_TEST_LAYOUT_PROVIDER_H_
+#define UI_VIEWS_TEST_TEST_LAYOUT_PROVIDER_H_
+
+#include <map>
+
+#include "base/macros.h"
+#include "ui/views/layout/layout_provider.h"
+
+namespace views {
+namespace test {
+
+// Helper to test LayoutProvider overrides.
+class TestLayoutProvider : public LayoutProvider {
+ public:
+  TestLayoutProvider();
+  ~TestLayoutProvider() override;
+
+  // Override requests for the |metric| DistanceMetric to return |value| rather
+  // than the default.
+  void SetDistanceMetric(int metric, int value);
+
+  // Override the return value of GetSnappedDialogWidth().
+  void SetSnappedDialogWidth(int width);
+
+  // LayoutProvider:
+  int GetDistanceMetric(int metric) const override;
+  int GetSnappedDialogWidth(int min_width) const override;
+
+ private:
+  std::map<int, int> distance_metrics_;
+  int snapped_dialog_width_ = 0;
+
+  DISALLOW_COPY_AND_ASSIGN(TestLayoutProvider);
+};
+
+}  // namespace test
+}  // namespace views
+
+#endif  // UI_VIEWS_TEST_TEST_LAYOUT_PROVIDER_H_