Coverity: Pass values by reference.

chrome/browser/memory_details.h

 // Copyright (c) 2010 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.
 
 #ifndef CHROME_BROWSER_MEMORY_DETAILS_H_
 #define CHROME_BROWSER_MEMORY_DETAILS_H_
 #pragma once
 
 #include <vector>
 
@@ skipping 104 matching lines @@
   // invokes back to the file thread to run the rest of the about:memory
   // functionality.
   void CollectChildInfoOnIOThread();
 
   // Collect current process information from the OS and store it
   // for processing.  If data has already been collected, clears old
   // data and re-collects the data.
   // Note - this function enumerates memory details from many processes
   // and is fairly expensive to run, hence it's run on the file thread.
   // The parameter holds information about processes from the IO thread.
-  void CollectProcessData(std::vector<ProcessMemoryInformation>);
+  void CollectProcessData(const std::vector<ProcessMemoryInformation>&);
 
 #if defined(OS_MACOSX)
   // A helper for |CollectProcessData()|, collecting data on the Chrome/Chromium
   // process with PID |pid|. The collected data is added to the state of the
   // object (in |process_data_|).
   void CollectProcessDataChrome(
       const std::vector<ProcessMemoryInformation>& child_info,
       base::ProcessId pid,
       const ProcessInfoSnapshot& process_info);
 #endif
 
   // Collect child process information on the UI thread.  Information about
   // renderer processes is only available there.
   void CollectChildInfoOnUIThread();
 
   // Each time we take a memory sample, we do a little work to update
   // the global histograms for tracking memory usage.
   void UpdateHistograms();
 
   // Returns a pointer to the ProcessData structure for Chrome.
   ProcessData* ChromeBrowser();
 
   std::vector<ProcessData> process_data_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryDetails);
 };
 
 #endif  // CHROME_BROWSER_MEMORY_DETAILS_H_