Make use of new hex decoding functions for native filesystem code.

Bug: 1021236
Change-Id: I884be77589493a3b7c605a1d9370facf82a1715c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1898708
Commit-Queue: Marijn Kruisselbrink <mek@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Auto-Submit: Eric Roman <eroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#713091}

chrome/browser/ui/views/native_file_system/native_file_system_browsertest.cc

@@ -273,11 +273,10 @@ IN_PROC_BROWSER_TEST_F(NativeFileSystemBrowserTest, FullscreenOpenFile) {
 IN_PROC_BROWSER_TEST_F(NativeFileSystemBrowserTest, SafeBrowsing) {
   const base::FilePath test_file = temp_dir_.GetPath().AppendASCII("test.exe");
 
-  std::vector<uint8_t> raw_expected_hash;
-  ASSERT_TRUE(base::HexStringToBytes(
+  std::string expected_hash;
+  ASSERT_TRUE(base::HexStringToString(
       "BA7816BF8F01CFEA414140DE5DAE2223B00361A396177A9CB410FF61F20015AD",
-      &raw_expected_hash));
-  std::string expected_hash(raw_expected_hash.begin(), raw_expected_hash.end());
+      &expected_hash));
   std::string expected_url =
       "blob:" + embedded_test_server()->base_url().spec() +
       "native-file-system-write";

content/browser/native_file_system/native_file_system_file_writer_impl_unittest.cc

@@ -522,11 +522,10 @@ TEST_F(NativeFileSystemFileWriterAfterWriteChecksTest, Allow) {
   EXPECT_EQ(result, NativeFileSystemStatus::kOk);
   EXPECT_EQ(bytes_written, 3u);
 
-  std::vector<uint8_t> raw_expected_hash;
-  ASSERT_TRUE(base::HexStringToBytes(
+  std::string expected_hash;
+  ASSERT_TRUE(base::HexStringToString(
       "BA7816BF8F01CFEA414140DE5DAE2223B00361A396177A9CB410FF61F20015AD",
-      &raw_expected_hash));
-  std::string expected_hash(raw_expected_hash.begin(), raw_expected_hash.end());
+      &expected_hash));
 
   EXPECT_CALL(
       permission_context_,