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

chrome/browser/worker_host/worker_process_host.cc

Index: chrome/browser/worker_host/worker_process_host.cc
diff --git a/chrome/browser/worker_host/worker_process_host.cc b/chrome/browser/worker_host/worker_process_host.cc
index 762a0c5134554cf253e401ad18bf3afa0401419e..f995cbd109e84a7a932d0c85e6ba7c4852da6f0d 100644
--- a/chrome/browser/worker_host/worker_process_host.cc
+++ b/chrome/browser/worker_host/worker_process_host.cc
@@ -107,8 +107,7 @@ bool WorkerProcessHost::Init() {
   CommandLine* cmd_line = new CommandLine(exe_path);
   cmd_line->AppendSwitchWithValue(switches::kProcessType,
                                   switches::kWorkerProcess);
-  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID,
-                                  ASCIIToWide(channel_id()));
+  cmd_line->AppendSwitchWithValue(switches::kProcessChannelID, channel_id());
   SetCrashReporterCommandLine(cmd_line);
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(
@@ -140,8 +139,7 @@ bool WorkerProcessHost::Init() {
     const std::wstring level =
         CommandLine::ForCurrentProcess()->GetSwitchValue(
             switches::kLoggingLevel);
-    cmd_line->AppendSwitchWithValue(
-        switches::kLoggingLevel, level);
+    cmd_line->AppendSwitchWithValue(switches::kLoggingLevel, level);
   }
 
   if (CommandLine::ForCurrentProcess()->HasSwitch(