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 "content/public/test/mock_download_item.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/test/views_test_base.h"
+
+class DownloadItemViewTest : public views::ViewsTestBase {
+ public:
+  DownloadItemViewTest() {
+    base::FilePath empty_file_path;
+    EXPECT_CALL(download_, GetTargetFilePath())
+        .WillRepeatedly(testing::ReturnRef(empty_file_path));
+    view_.reset(new DownloadItemView(&download_, nullptr));
+  }
+
+  void SetDownloadWarningLabelAndResize(const base::string16& label_text) {
+    view_->dangerous_download_label_sized_ = false;
+    view_->dangerous_download_label_->SetText(label_text);
+    view_->dangerous_download_label_->SetMultiLine(true);
+    view_->dangerous_download_label_->SetHorizontalAlignment(gfx::ALIGN_LEFT);
+    view_->dangerous_download_label_->SetAutoColorReadabilityEnabled(false);
+    view_->SizeLabelToMinWidth();
+  }
+
+  base::string16 GetLabelText() const {
+    return view_->dangerous_download_label_->text();
+  }
+
+ private:
+  content::MockDownloadItem download_;
+  std::unique_ptr<DownloadItemView> view_;
+  DISALLOW_COPY_AND_ASSIGN(DownloadItemViewTest);

[Peter Kasting, 2016/12/08 05:10:23]

Nit: Suggest a blank line above this

[Jialiu Lin, 2016/12/08 07:47:40]

Done.

+};
+
+// For very short label that can fit in a single line, no need to do any
+// adjustment, return it directly.
+TEST_F(DownloadItemViewTest, SizeLabelToMinWidth_VeryShortText) {
+  base::string16 label_text = base::ASCIIToUTF16("very short label");
+  SetDownloadWarningLabelAndResize(label_text);
+  EXPECT_EQ(label_text, GetLabelText());
+}
+
+// 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(DownloadItemViewTest, SizeLabelToMinWidth_MoreTextOnFirstLine) {
+  base::string16 label_text = base::ASCIIToUTF16(
+      "aaaa aaaa aaaa aaaa aaaa aaaa bb aaaa aaaa aaaa aaaa aaaa aaaa");
+  SetDownloadWarningLabelAndResize(label_text);
+  base::string16 expected_text = base::ASCIIToUTF16(
+      "aaaa aaaa aaaa aaaa aaaa aaaa bb\n"
+      "aaaa aaaa aaaa aaaa aaaa aaaa");
+  EXPECT_EQ(expected_text, GetLabelText());
+}
+
+// If the label is a single word and extremely long, we should not break it into
+// 2 lines.
+TEST_F(DownloadItemViewTest, SizeLabelToMinWidth_VeryLongTextWithoutSpace) {
+  base::string16 label_text = base::ASCIIToUTF16(
+      "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa");
+  SetDownloadWarningLabelAndResize(label_text);
+  EXPECT_EQ(label_text, GetLabelText());
+}