Remove NaCl.Startups histogram, this data is tracked in the NaCl plugin now

chrome/browser/nacl_host/nacl_process_host.cc

 // Copyright (c) 2011 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 "build/build_config.h"
 
 #include "chrome/browser/nacl_host/nacl_process_host.h"
 
 #if defined(OS_POSIX)
 #include <fcntl.h>
 #endif
 
 #include "base/command_line.h"
-#include "base/metrics/nacl_histogram.h"
 #include "base/path_service.h"
 #include "base/utf_string_conversions.h"
 #include "base/win/windows_version.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/logging_chrome.h"
 #include "chrome/common/nacl_cmd_line.h"
 #include "chrome/common/nacl_messages.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/browser/renderer_host/chrome_render_message_filter.h"
@@ skipping 96 matching lines @@
     internal_->sockets_for_renderer.push_back(pair[0]);
     internal_->sockets_for_sel_ldr.push_back(pair[1]);
     SetCloseOnExec(pair[0]);
     SetCloseOnExec(pair[1]);
   }
 
   // Launch the process
   if (!LaunchSelLdr()) {
     return false;
   }
-  UmaNaclHistogramEnumeration(NACL_STARTED);
   chrome_render_message_filter_ = chrome_render_message_filter;
   reply_msg_ = reply_msg;
 
   return true;
 #endif  // DISABLE_NACL
 }
 
 bool NaClProcessHost::LaunchSelLdr() {
   if (!CreateChannel())
     return false;
@@ skipping 220 matching lines @@
 }
 
 bool NaClProcessHost::OnMessageReceived(const IPC::Message& msg) {
   NOTREACHED() << "Invalid message with type = " << msg.type();
   return false;
 }
 
 bool NaClProcessHost::CanShutdown() {
   return true;
 }