Make use of new hex decoding functions for //base code.

Bug: 1021236
Change-Id: I96599537914475508a3404b4771aeab9fa117a05
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1896341
Auto-Submit: Eric Roman <eroman@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712481}

base/test/scoped_feature_list.cc

@@ -116,10 +116,10 @@ std::string HexEncodeString(const std::string& input) {
 std::string HexDecodeString(const std::string& input) {
   if (input.empty())
     return std::string();
-  std::vector<uint8_t> bytes;
-  bool result = HexStringToBytes(input, &bytes);
+  std::string bytes;
+  bool result = HexStringToString(input, &bytes);
   DCHECK(result);
-  return std::string(reinterpret_cast<const char*>(&bytes[0]), bytes.size());
+  return bytes;
 }
 
 }  // namespace

base/value_conversions.cc

@@ -92,20 +92,11 @@ bool GetValueAsUnguessableToken(const Value& value, UnguessableToken* token) {
     return false;
   }
 
-  // TODO(dcheng|yucliu): Make a function that accepts non vector variant and
-  // reads a fixed number of bytes.
-  std::vector<uint8_t> high_low_bytes;
-  if (!HexStringToBytes(value.GetString(), &high_low_bytes)) {
-    return false;
-  }
-
   UnguessableTokenRepresentation representation;
-  if (high_low_bytes.size() != sizeof(representation.buffer)) {
+  if (!HexStringToSpan(value.GetString(), representation.buffer)) {
     return false;
   }
 
-  std::copy(high_low_bytes.begin(), high_low_bytes.end(),
-            std::begin(representation.buffer));
   *token = UnguessableToken::Deserialize(representation.field.high,
                                          representation.field.low);
   return true;