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/Plugins/Language/CPlusPlus/LibCxxVector.cpp b/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
index c3bf9f8..b7ed597 100644
--- a/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
+++ b/lldb/source/Plugins/Language/CPlusPlus/LibCxxVector.cpp
@@ -32,7 +32,7 @@
 
   bool MightHaveChildren() override;
 
-  size_t GetIndexOfChildWithName(const ConstString &name) override;
+  size_t GetIndexOfChildWithName(ConstString name) override;
 
 private:
   ValueObject *m_start;
@@ -53,7 +53,7 @@
 
   bool MightHaveChildren() override { return true; }
 
-  size_t GetIndexOfChildWithName(const ConstString &name) override;
+  size_t GetIndexOfChildWithName(ConstString name) override;
 
 private:
   CompilerType m_bool_type;
@@ -164,7 +164,7 @@
 }
 
 size_t lldb_private::formatters::LibcxxStdVectorSyntheticFrontEnd::
-    GetIndexOfChildWithName(const ConstString &name) {
+    GetIndexOfChildWithName(ConstString name) {
   if (!m_start || !m_finish)
     return UINT32_MAX;
   return ExtractIndexFromString(name.GetCString());
@@ -271,7 +271,7 @@
 }
 
 size_t lldb_private::formatters::LibcxxVectorBoolSyntheticFrontEnd::
-    GetIndexOfChildWithName(const ConstString &name) {
+    GetIndexOfChildWithName(ConstString name) {
   if (!m_count || !m_base_data_address)
     return UINT32_MAX;
   const char *item_name = name.GetCString();