Avoid the use of std::char_traits<> for non-character type

libc++ is deprecating std::char_traits for types other than char,
wchar_t and the like.

Bug: 1393769
Change-Id: Ic24de0b92feff2c46db77910c9629d0d34409cce
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4058321
Auto-Submit: Hans Wennborg <hans@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1075907}

components/speech/chunked_byte_buffer_unittest.cc

@@ -4,6 +4,7 @@
 
 #include <stdint.h>
 
+#include <cstring>
 #include <string>
 #include <vector>
 
@@ -46,17 +47,15 @@ TEST(ChunkedByteBufferTest, BasicTest) {
   chunk = buffer.PopChunk();
   EXPECT_TRUE(chunk != nullptr);
   EXPECT_EQ(4U, chunk->size());
-  EXPECT_EQ(0, std::char_traits<uint8_t>::compare(kChunks + 4, &(*chunk)[0],
-                                                  chunk->size()));
+  EXPECT_EQ(0, std::memcmp(kChunks + 4, chunk->data(), chunk->size()));
   EXPECT_EQ(6U, buffer.GetTotalLength());
   EXPECT_TRUE(buffer.HasChunks());
 
   // Read and check chunk 2.
   chunk = buffer.PopChunk();
   EXPECT_TRUE(chunk != nullptr);
   EXPECT_EQ(2U, chunk->size());
-  EXPECT_EQ(0, std::char_traits<uint8_t>::compare(kChunks + 12, &(*chunk)[0],
-                                                  chunk->size()));
+  EXPECT_EQ(0, std::memcmp(kChunks + 12, chunk->data(), chunk->size()));
   EXPECT_EQ(0U, buffer.GetTotalLength());
   EXPECT_FALSE(buffer.HasChunks());