Add fileManagerPrivate getContentMimeType getContentMetadata tests

Test files come from //media/test/data. Change apitest C++ to copy the
files to the 'testing' Volume before starting tests.

  id3_png_test.mp3: audio file with embedded album artwork image
  90rotation.mp4: h264 video, with 90 degree rotation, no images

Add test JS helpers to read the files from the 'testing' volume / file
system and convert them to Blobs before starting the tests.

Add fileManagerPrivate.getContentMimeType mime sniffing tests:

 testGetContentMimeTypeEmpty
   - input is an empty blob, returns undefined mimeType result
 testGetContentMimeTypeImage
   - input is an image file blob, sniff image/gif
 testGetContentMimeTypeAudio
   - input is an audio file blob, sniff audio/mpeg
 testGetContentMimeTypeVideo
   - input is a video file blob, sniff video/mp4
 testGetContentMimeTypeUnknownMimeTypeError
   - net::mime_sniffer fails, sets chrome.runtime.LastError

Add fileManagerPrivate.getContentMetadata metadata extraction tests:

 testGetContentMetadataEmpty
   - input is an empty blob, returns undefined MediaMetadata
 testGetContentMetadataAudioTags
   - extract tags only into the MediaMetadata result
   - vet result with JS verifyExpectedAudioMetadata() helper
 testGetContentMetadataAudioTagsImages
   - extract tags and images into the MediaMetadata result
   - vet result with JS verifyExpectedAudioMetadata() helper
 testGetContentMetadataVideoTagsImages
   - extract tags and images into the MediaMetadata result
   - vet result with verifyExpectedVideoMetadata() helper
 testGetContentMetadataRetainsInputMimeType
   - input mime type is copied through to MediaMetadata.mimeType
 testGetContentMetadataVideoResetsAudioMime
   - audio mime is changed to video if there is width and height
 testGetContentMetadataUnsupportedMimetypeError
   - input mime not video or audio, sets chrome.runtime.LastError

Bug: 1114622
Change-Id: Ic96ce7faa409ae25d6b3c956666bbfd7db362f25
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2345936
Commit-Queue: Noel Gordon <noel@chromium.org>
Reviewed-by: Naoki Fukino <fukino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797078}

chrome/browser/chromeos/extensions/file_manager/file_manager_private_apitest.cc

-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright 2012 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.
 
@@ -9,6 +9,7 @@
 
 #include "base/base64.h"
 #include "base/bind.h"
+#include "base/path_service.h"
 #include "base/run_loop.h"
 #include "base/stl_util.h"
 #include "chrome/browser/chromeos/crostini/crostini_manager.h"
@@ -463,6 +464,35 @@ IN_PROC_BROWSER_TEST_F(FileManagerPrivateApiTest, Recent) {
   ASSERT_TRUE(RunComponentExtensionTest("file_browser/recent_test"));
 }
 
+IN_PROC_BROWSER_TEST_F(FileManagerPrivateApiTest, MediaMetadata) {
+  const base::FilePath test_dir = temp_dir_.GetPath();
+  AddLocalFileSystem(browser()->profile(), test_dir);
+
+  // Get the source tree media/test/data directory path.
+  base::FilePath root_dir;
+  CHECK(base::PathService::Get(base::DIR_SOURCE_ROOT, &root_dir));
+  const base::FilePath media_test_data_dir =
+      root_dir.AppendASCII("media").AppendASCII("test").AppendASCII("data");
+
+  // Returns a path to a media/test/data test file.
+  auto get_media_test_data_file = [&](const std::string& file) {
+    return media_test_data_dir.Append(base::FilePath::FromUTF8Unsafe(file));
+  };
+
+  // Create test files.
+  {
+    base::ScopedAllowBlockingForTesting allow_io;
+
+    const base::FilePath video = get_media_test_data_file("90rotation.mp4");
+    ASSERT_TRUE(base::CopyFile(video, test_dir.Append(video.BaseName())));
+
+    const base::FilePath audio = get_media_test_data_file("id3_png_test.mp3");
+    ASSERT_TRUE(base::CopyFile(audio, test_dir.Append(audio.BaseName())));
+  }
+
+  ASSERT_TRUE(RunComponentExtensionTest("file_browser/media_metadata"));
+}
+
 IN_PROC_BROWSER_TEST_F(FileManagerPrivateApiTest, Crostini) {
   crostini::FakeCrostiniFeatures crostini_features;
   crostini_features.set_ui_allowed(true);

chrome/test/data/extensions/api_test/file_browser/media_metadata/manifest.json

+{
+  // chrome-extension://pkplfbidichfdicaijlchgnapepdginl
+  "key": "MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAtDfX9dHNh948bt00YhZBm3P6E5QLaOt+v8kXVtibQfiPtOD2FTScB/f0wX/EQWVO7BkaSOsRkTPcPIgocyMPYr2FLgqGLFlYT9nQpKJZUFNF5oJ5rG6Nv7ppf4zEB3j6da1IBRTz2yOZ+6O1TMZxol/V62/QcqrJeggsHTEPGLdr9Ua4b1Ka0xKJnJngZljsbw93FI1o+P9dAh5BS6wTPiZI/vmJVjvMTkSTnaZ3n9Go2t7A0XLcSxLcVyuLAd2mAvSN0mIviOukdM66wr7llif71nKuUt+4qvlr/r9HfwzN6pA4jkwhtS1UD+3CmB+wsHwsnohNcuu4FIQ6rgq/7QIDAQAB",
+  "name": "chrome.fileManagerPrivate tests",
+  "version": "0.1",
+  "manifest_version": 2,
+  "description": "Tests chrome.fileManagerPrivate.getContetMimeType and getContentMetadata",
+  "app": {
+    "background": {
+      "scripts": ["test.js"]
+    }
+  },
+  "permissions": [
+    "fileManagerPrivate",
+    {
+      "fileSystem": ["requestFileSystem"]
+    }
+  ]
+}