Sync with upstream repo.

Changes include:
* CPU check has been broken up into a number of small libraries
* BoringSSL option has been removed
* Better abseil integration

compressor.h

@@ -0,0 +1,49 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef THIRD_PARTY_CPU_CHECK_COMPRESSOR_H_
+#define THIRD_PARTY_CPU_CHECK_COMPRESSOR_H_
+
+#include <string>
+
+#include "malign_buffer.h"
+#include "absl/status/status.h"
+
+namespace cpu_check {
+
+class Compressor {
+ public:
+  virtual ~Compressor() {}
+  virtual std::string Name() const = 0;
+
+  // Compresses 'm' into 'compressed'.
+  virtual absl::Status Compress(const MalignBuffer &m,
+                                MalignBuffer *compressed) const = 0;
+
+  // Decompresses 'compressed' into 'm'.
+  virtual absl::Status Decompress(const MalignBuffer &compressed,
+                                  MalignBuffer *m) const = 0;
+};
+
+class Zlib : public Compressor {
+ public:
+  std::string Name() const override { return "ZLIB"; }
+  absl::Status Compress(const MalignBuffer &m,
+                        MalignBuffer *compressed) const override;
+  absl::Status Decompress(const MalignBuffer &compressed,
+                          MalignBuffer *m) const override;
+};
+
+};      // namespace cpu_check
+#endif  // THIRD_PARTY_CPU_CHECK_COMPRESSOR_H_