Implement manifest icon downloader

chrome/browser/manifest/manifest_icon_downloader_unittest.cc

+// Copyright 2015 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/manifest/manifest_icon_downloader.h"
+
+#include <string>
+#include <vector>
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+class ManifestIconDownloaderTest : public testing::Test  {
+ protected:
+  ManifestIconDownloaderTest() {}
+  ~ManifestIconDownloaderTest() override = default;
+
+  int FindBitmap(const int ideal_icon_size_in_px,
+                 const std::vector<SkBitmap>& bitmaps) {
+    return ManifestIconDownloader::FindClosestBitmapIndex(
+        ideal_icon_size_in_px, bitmaps);
+  }
+
+  SkBitmap CreateBitmap(int width, int height) {
+    SkBitmap bitmap;
+    bitmap.allocN32Pixels(width, height);
+    bitmap.setImmutable();
+    return bitmap;
+  }
+
+  DISALLOW_COPY_AND_ASSIGN(ManifestIconDownloaderTest);
+};
+
+TEST_F(ManifestIconDownloaderTest, NoIcons) {
+  ASSERT_EQ(-1, FindBitmap(0, std::vector<SkBitmap>()));
+}
+
+TEST_F(ManifestIconDownloaderTest, ExactIsChosen) {
+  std::vector<SkBitmap> vector { CreateBitmap(10, 10) };
+  ASSERT_EQ(0, FindBitmap(10, vector));
+}
+
+TEST_F(ManifestIconDownloaderTest, BiggerIsChosen) {
+  std::vector<SkBitmap> vector { CreateBitmap(20, 20) };
+  ASSERT_EQ(0, FindBitmap(10, vector));
+}
+
+TEST_F(ManifestIconDownloaderTest, SmallerIsIgnored) {
+  std::vector<SkBitmap> vector { CreateBitmap(10, 10) };
+  ASSERT_EQ(-1, FindBitmap(20, vector));
+}
+
+TEST_F(ManifestIconDownloaderTest, ExactIsPreferredOverBigger) {
+  std::vector<SkBitmap> vector { CreateBitmap(20, 20), CreateBitmap(10, 10) };
+  ASSERT_EQ(1, FindBitmap(10, vector));
+}
+
+TEST_F(ManifestIconDownloaderTest, ExactIsPreferredOverSmaller) {
+  std::vector<SkBitmap> vector { CreateBitmap(10, 10), CreateBitmap(20, 20) };
+  ASSERT_EQ(1, FindBitmap(20, vector));
+}
+
+TEST_F(ManifestIconDownloaderTest, ClosestToExactIsChosen) {
+  std::vector<SkBitmap> vector { CreateBitmap(20, 20), CreateBitmap(25, 25) };
+  ASSERT_EQ(0, FindBitmap(10, vector));
+}
+
+TEST_F(ManifestIconDownloaderTest, ClosestToExactIsChosenUnordered) {
+  std::vector<SkBitmap> vector { CreateBitmap(25, 25), CreateBitmap(20, 20) };
+  ASSERT_EQ(1, FindBitmap(10, vector));
+}