CommandLine: add a CopySwitchesFrom() for copying from another CommandLine

chrome/browser/zygote_host_linux.cc

 // 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.
 
 #include "chrome/browser/zygote_host_linux.h"
 
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
@@ skipping 78 matching lines @@
     switches::kLoggingLevel,
     switches::kEnableLogging,  // Support, e.g., --enable-logging=stderr.
     switches::kUserDataDir,  // Make logs go to the right file.
     // Load (in-process) Pepper plugins in-process in the zygote pre-sandbox.
     switches::kRegisterPepperPlugins,
 #if defined(USE_SECCOMP_SANDBOX)
     switches::kDisableSeccompSandbox,
 #else
     switches::kEnableSeccompSandbox,
 #endif
-    NULL
   };
-  for (const char** sw = kForwardSwitches; *sw; sw++) {
-    if (browser_command_line.HasSwitch(*sw)) {
-      // Always append with value for those switches which need it; it does no
-      // harm for those which don't.
-      cmd_line.AppendSwitchWithValue(*sw,
-          browser_command_line.GetSwitchValueASCII(*sw));
-    }
-  }
+  cmd_line.CopySwitchesFrom(browser_command_line, kForwardSwitches,
+                            arraysize(kForwardSwitches));
 
   sandbox_binary_ = sandbox_cmd.c_str();
   struct stat st;
 
   if (!sandbox_cmd.empty() && stat(sandbox_binary_.c_str(), &st) == 0) {
     if (access(sandbox_binary_.c_str(), X_OK) == 0 &&
         (st.st_uid == 0) &&
         (st.st_mode & S_ISUID) &&
         (st.st_mode & S_IXOTH)) {
       using_suid_sandbox_ = true;
@@ skipping 220 matching lines @@
       !read_pickle.ReadBool(&iter, &tmp_child_exited)) {
     LOG(WARNING) << "Error parsing DidProcessCrash response from zygote.";
     return false;
   }
 
   if (child_exited)
     *child_exited = tmp_child_exited;
 
   return did_crash;
 }