Make MetricsService upload logs through an interface.

components/metrics/net/compression_utils_unittest.cc

+// Copyright 2014 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 "components/metrics/net/compression_utils.h"
+
+#include <string>
+
+#include "base/base_paths.h"
+#include "base/basictypes.h"
+#include "base/file_util.h"
+#include "base/path_service.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace metrics {
+
+namespace {
+
+// The data to be compressed by gzip. This is the hex representation of "hello
+// world".
+const uint8 kData[] =
+    {0x68, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x77, 0x6f,
+     0x72, 0x6c, 0x64};
+
+// This is the string representation of gzip compressed string above. It was
+// obtained by running echo -n "hello world" | gzip -c | hexdump -e '8 1 ",
+// 0x%x"' followed by 0'ing out the OS byte (10th byte) in the header. This is
+// so that the test passes on all platforms (that run various OS'es).
+const uint8 kCompressedData[] =
+    {0x1f, 0x8b, 0x08, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+     0x00, 0xcb, 0x48, 0xcd, 0xc9, 0xc9, 0x57, 0x28, 0xcf,
+     0x2f, 0xca, 0x49, 0x01, 0x00, 0x85, 0x11, 0x4a, 0x0d,
+     0x0b, 0x00, 0x00, 0x00};
+
+// Re-enable C4309.
+#if defined(OS_WIN)
+#pragma warning( default: 4309 )
+#endif
+
+}  // namespace
+
+TEST(CompressionUtilsTest, GzipCompression) {
+  std::string data(reinterpret_cast<const char*>(kData), arraysize(kData));
+  std::string compressed_data;
+  EXPECT_TRUE(GzipCompress(data, &compressed_data));
+  std::string golden_compressed_data(
+      reinterpret_cast<const char*>(kCompressedData),
+      arraysize(kCompressedData));
+  EXPECT_EQ(golden_compressed_data, compressed_data);
+}
+
+}  // namespace metrics