Pass ConstString by value (NFC)

My apologies for the large patch. With the exception of ConstString.h
itself it was entirely produced by sed.

ConstString has exactly one const char * data member, so passing a
ConstString by reference is not any more efficient than copying it by
value. In both cases a single pointer is passed. But passing it by
value makes it harder to accidentally return the address of a local
object.

(This fixes rdar://problem/48640859 for the Apple folks)

Differential Revision: https://reviews.llvm.org/D59030

llvm-svn: 355553
diff --git a/lldb/source/Target/ObjCLanguageRuntime.cpp b/lldb/source/Target/ObjCLanguageRuntime.cpp
index fac1fae..cd97707 100644
--- a/lldb/source/Target/ObjCLanguageRuntime.cpp
+++ b/lldb/source/Target/ObjCLanguageRuntime.cpp
@@ -153,7 +153,7 @@
 }
 
 ObjCLanguageRuntime::ObjCISA
-ObjCLanguageRuntime::GetISA(const ConstString &name) {
+ObjCLanguageRuntime::GetISA(ConstString name) {
   ISAToDescriptorIterator pos = GetDescriptorIterator(name);
   if (pos != m_isa_to_descriptor.end())
     return pos->first;
@@ -161,7 +161,7 @@
 }
 
 ObjCLanguageRuntime::ISAToDescriptorIterator
-ObjCLanguageRuntime::GetDescriptorIterator(const ConstString &name) {
+ObjCLanguageRuntime::GetDescriptorIterator(ConstString name) {
   ISAToDescriptorIterator end = m_isa_to_descriptor.end();
 
   if (name) {
@@ -226,7 +226,7 @@
 
 ObjCLanguageRuntime::ClassDescriptorSP
 ObjCLanguageRuntime::GetClassDescriptorFromClassName(
-    const ConstString &class_name) {
+    ConstString class_name) {
   ISAToDescriptorIterator pos = GetDescriptorIterator(class_name);
   if (pos != m_isa_to_descriptor.end())
     return pos->second;