Revert of Add new HTTP/2 and HPACK decoder in net/http2/.

net/http2/hpack/tools/hpack_example.cc

-// Copyright 2016 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 "net/http2/hpack/tools/hpack_example.h"
-
-#include <ctype.h>
-
-#include "base/logging.h"
-#include "net/spdy/spdy_test_utils.h"
-
-using base::StringPiece;
-using std::string;
-
-namespace net {
-namespace test {
-namespace {
-
-void HpackExampleToStringOrDie(StringPiece example, string* output) {
-  while (!example.empty()) {
-    const char c0 = example[0];
-    if (isxdigit(c0)) {
-      CHECK_GT(example.size(), 1u) << "Truncated hex byte?";
-      const char c1 = example[1];
-      CHECK(isxdigit(c1)) << "Found half a byte?";
-      *output += a2b_hex(example.substr(0, 2).as_string().c_str());
-      example.remove_prefix(2);
-      continue;
-    }
-    if (isspace(c0)) {
-      example.remove_prefix(1);
-      continue;
-    }
-    if (example.starts_with("|")) {
-      // Start of a comment. Skip to end of line or of input.
-      auto pos = example.find('\n');
-      if (pos == StringPiece::npos) {
-        // End of input.
-        break;
-      }
-      example.remove_prefix(pos + 1);
-      continue;
-    }
-    CHECK(false) << "Can't parse byte " << static_cast<int>(c0) << " (0x"
-                 << std::hex << c0 << ")"
-                 << "\nExample: " << example;
-  }
-  CHECK_LT(0u, output->size()) << "Example is empty.";
-  return;
-}
-
-}  // namespace
-
-string HpackExampleToStringOrDie(StringPiece example) {
-  string output;
-  HpackExampleToStringOrDie(example, &output);
-  return output;
-}
-
-}  // namespace test
-}  // namespace net