DebugInfoPDB: Make the symbol base case hold an IPDBSession ref.

Dumping a symbol often requires access to data that isn't inside
the symbol hierarchy, but which is only accessible through the
top-level session.  This patch is a pure interface change to give
symbols a reference to the session.

llvm-svn: 228542
diff --git a/llvm/lib/DebugInfo/PDB/PDBSymbolFuncDebugEnd.cpp b/llvm/lib/DebugInfo/PDB/PDBSymbolFuncDebugEnd.cpp
index 03e60c1..a88ea2a 100644
--- a/llvm/lib/DebugInfo/PDB/PDBSymbolFuncDebugEnd.cpp
+++ b/llvm/lib/DebugInfo/PDB/PDBSymbolFuncDebugEnd.cpp
@@ -15,7 +15,7 @@
 using namespace llvm;
 
 PDBSymbolFuncDebugEnd::PDBSymbolFuncDebugEnd(
-    std::unique_ptr<IPDBRawSymbol> Symbol)
-    : PDBSymbol(std::move(Symbol)) {}
+    IPDBSession &PDBSession, std::unique_ptr<IPDBRawSymbol> Symbol)
+    : PDBSymbol(Session, std::move(Symbol)) {}
 
 void PDBSymbolFuncDebugEnd::dump(llvm::raw_ostream &OS) const {}