[lldb][NFCI] Remove use of ConstString from IOHandler

None of these need to be in the ConstString StringPool. For the most
part they are constant strings and do not require fast comparisons.

I did change IOHandlerDelegateMultiline slightly -- specifically, the
`m_end_line` member always has a `\n` at the end of it now. This was so
that `IOHandlerGetControlSequence` can always return a StringRef. This
did require a slight change to `IOHandlerIsInputComplete` where we must
drop the newline before comparing it against the input parameter.

Differential Revision: https://reviews.llvm.org/D151597

1 files changed, 6 insertions, 5 deletions

diff --git a/lldb/source/API/SBCommandInterpreter.cpp b/lldb/source/API/SBCommandInterpreter.cpp
index 9ea7200..396c0ee 100644
--- a/lldb/source/API/SBCommandInterpreter.cpp
+++ b/lldb/source/API/SBCommandInterpreter.cpp
@@ -155,11 +155,12 @@ bool SBCommandInterpreter::InterruptCommand() {
 const char *SBCommandInterpreter::GetIOHandlerControlSequence(char ch) {
   LLDB_INSTRUMENT_VA(this, ch);
 
-  return (IsValid()
-              ? m_opaque_ptr->GetDebugger()
-                    .GetTopIOHandlerControlSequence(ch)
-                    .GetCString()
-              : nullptr);
+  if (!IsValid())
+    return nullptr;
+
+  return ConstString(
+             m_opaque_ptr->GetDebugger().GetTopIOHandlerControlSequence(ch))
+      .GetCString();
 }
 
 lldb::ReturnStatus