Modernize Enable/DisableLogChannel interface a bit

Summary:
Use StringRef and ArrayRef where possible. This adds an accessor to the
Args class to get a view of the arguments as ArrayRef<const char *>.

Reviewers: zturner

Subscribers: lldb-commits

Differential Revision: https://reviews.llvm.org/D30402

llvm-svn: 296592
diff --git a/lldb/source/Commands/CommandObjectLog.cpp b/lldb/source/Commands/CommandObjectLog.cpp
index c10f868..9760963 100644
--- a/lldb/source/Commands/CommandObjectLog.cpp
+++ b/lldb/source/Commands/CommandObjectLog.cpp
@@ -172,8 +172,8 @@
     else
       log_file[0] = '\0';
     bool success = m_interpreter.GetDebugger().EnableLog(
-        channel.c_str(), args.GetConstArgumentVector(), log_file,
-        m_options.log_options, result.GetErrorStream());
+        channel, args.GetArgumentArrayRef(), log_file, m_options.log_options,
+        result.GetErrorStream());
     if (success)
       result.SetStatus(eReturnStatusSuccessFinishNoResult);
     else
@@ -233,7 +233,7 @@
       Log::DisableAllLogChannels(&result.GetErrorStream());
       result.SetStatus(eReturnStatusSuccessFinishNoResult);
     } else {
-      if (Log::DisableLogChannel(channel, args.GetConstArgumentVector(),
+      if (Log::DisableLogChannel(channel, args.GetArgumentArrayRef(),
                                  result.GetErrorStream()))
         result.SetStatus(eReturnStatusSuccessFinishNoResult);
     }