Implement GetCPUUsage; it was causing link errors because of its absence on t...

base/process_util_linux.cc

 // Copyright (c) 2008 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 "base/process_util.h"
 
 #include <ctype.h>
 #include <dirent.h>
 #include <string>
 #include <sys/types.h>
@@ skipping 304 matching lines @@
         } else if (last_key_name == "wchar") {
           (*io_counters).WriteTransferCount = StringToInt64(tokenizer.token());
         }
         state = KEY_NAME;
         break;
     }
   }
   return true;
 }
 
-int ProcessMetrics::GetCPUUsage() {
-  // TODO(port): This needs to be replaced by an call to getrusage().
-  return -1;
-}
-
 }  // namespace base