Per kmixter's suggestion, install metrics headers under /usr/include/metrics.

src/platform/crash/user_collector.cc

 // 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.
 
 #include <string>
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "crash/user_collector.h"
-#include "metrics_library.h"
+#include "metrics/metrics_library.h"
 
 // This procfs file is used to cause kernel core file writing to
 // instead pipe the core file into a user space process.  See
 // core(5) man page.
 static const char kCorePatternFile[] = "/proc/sys/kernel/core_pattern";
 
 UserCollector::UserCollector()
     : core_pattern_file_(kCorePatternFile),
       count_crash_function_(NULL),
       initialized_(false),
@@ skipping 44 matching lines @@
 
 void UserCollector::HandleCrash(int signal, int pid, const std::string &exec) {
   CHECK(initialized_);
   logger_->LogWarning("Received crash notification for %s[%d] sig %d",
                       exec.c_str(), pid, signal);
 
   if (is_feedback_allowed_function_()) {
     count_crash_function_();
   }
 }