Fix SizeLabelToMinWidth() function such that no unnecessary space

chrome/browser/ui/views/download/download_item_view_unittest.cc

+// 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.
+
+#include "chrome/browser/ui/views/download/download_item_view.h"
+
+#include "base/strings/utf_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/views/controls/label.h"
+
+typedef testing::Test DownloadItemViewDangerousDownloadLabelTest;

[Peter Kasting, 2016/12/08 21:53:53]

Nit: Prefer type alias ("using") to typedef.

[Jialiu Lin, 2016/12/08 22:44:03]

Done.

+
+// For very short label that can fit in a single line, no need to do any
+// adjustment, return it directly.
+TEST_F(DownloadItemViewDangerousDownloadLabelTest,
+       AdjustTextAndGetSize_VeryShortText) {
+  base::string16 label_text = base::ASCIIToUTF16("very short label");

[Peter Kasting, 2016/12/08 21:53:53]

Nit: I suggest just "short", to minimize the chance this gets anywhere close to
the wrap length.

[Jialiu Lin, 2016/12/08 22:44:03]

Done.

+  views::Label label(label_text);
+  label.SetMultiLine(true);
+  DownloadItemView::AdjustTextAndGetSize(&label);
+  EXPECT_EQ(label_text, label.text());
+}
+
+// When we have multiple linebreaks that result in the same minimum width, we
+// should place as much text as possible on the first line.
+TEST_F(DownloadItemViewDangerousDownloadLabelTest,
+       AdjustTextAndGetSize_MoreTextOnFirstLine) {
+  base::string16 label_text = base::ASCIIToUTF16(
+      "aaaa aaaa aaaa aaaa aaaa aaaa bb aaaa aaaa aaaa aaaa aaaa aaaa");
+  base::string16 expected_text = base::ASCIIToUTF16(
+      "aaaa aaaa aaaa aaaa aaaa aaaa bb\n"
+      "aaaa aaaa aaaa aaaa aaaa aaaa");
+  views::Label label(label_text);
+  label.SetMultiLine(true);
+  DownloadItemView::AdjustTextAndGetSize(&label);
+  EXPECT_EQ(expected_text, label.text());
+}
+
+// If the label is a single word and extremely long, we should not break it into
+// 2 lines.
+TEST_F(DownloadItemViewDangerousDownloadLabelTest,
+       AdjustTextAndGetSize_VeryLongTextWithoutSpace) {
+  base::string16 label_text = base::ASCIIToUTF16(
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
+  views::Label label(label_text);
+  label.SetMultiLine(true);
+  DownloadItemView::AdjustTextAndGetSize(&label);
+  EXPECT_EQ(label_text, label.text());
+}