add C wrapper for libmetrics

TEST=unit tests + build&test crosmetrics plugin for flimflam

Review URL: http://codereview.chromium.org/2832008
diff --git a/metrics/c_metrics_library.cc b/metrics/c_metrics_library.cc
new file mode 100644
index 0000000..91e9ca6
--- /dev/null
+++ b/metrics/c_metrics_library.cc
@@ -0,0 +1,44 @@
+// Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+//
+// C wrapper to libmetrics
+//
+
+#include "c_metrics_library.h"
+#include "metrics_library.h"
+
+extern "C" CMetricsLibrary CMetricsLibraryNew(void) {
+  MetricsLibrary* lib = new MetricsLibrary;
+  return reinterpret_cast<CMetricsLibrary>(lib);
+}
+
+extern "C" void CMetricsLibraryDelete(CMetricsLibrary handle) {
+  MetricsLibrary* lib = reinterpret_cast<MetricsLibrary*>(handle);
+  delete lib;
+}
+
+extern "C" void CMetricsLibraryInit(CMetricsLibrary handle) {
+  MetricsLibrary* lib = reinterpret_cast<MetricsLibrary*>(handle);
+  if (lib != NULL)
+    lib->Init();
+}
+
+extern "C" int CMetricsLibrarySendToUMA(CMetricsLibrary handle,
+					const char* name, int sample,
+					int min, int max, int nbuckets) {
+  MetricsLibrary* lib = reinterpret_cast<MetricsLibrary*>(handle);
+  if (lib == NULL)
+    return 0;
+  return lib->SendToUMA(std::string(name), sample, min, max, nbuckets);
+}
+
+extern "C" int CMetricsLibrarySendEnumToUMA(CMetricsLibrary handle,
+					    const char* name, int sample,
+					    int max) {
+  MetricsLibrary* lib = reinterpret_cast<MetricsLibrary*>(handle);
+  if (lib == NULL)
+    return 0;
+  return lib->SendEnumToUMA(std::string(name), sample, max);
+}