[PDB] Remove unused private variable, re-applying r327900 after relanding more natvis changes[4~

llvm-svn: 328156
diff --git a/llvm/lib/DebugInfo/PDB/DIA/DIAInjectedSource.cpp b/llvm/lib/DebugInfo/PDB/DIA/DIAInjectedSource.cpp
index fbd1695..1d642f2 100644
--- a/llvm/lib/DebugInfo/PDB/DIA/DIAInjectedSource.cpp
+++ b/llvm/lib/DebugInfo/PDB/DIA/DIAInjectedSource.cpp
@@ -16,9 +16,8 @@
 using namespace llvm;
 using namespace llvm::pdb;
 
-DIAInjectedSource::DIAInjectedSource(const DIASession &Session,
-                                     CComPtr<IDiaInjectedSource> DiaSourceFile)
-    : Session(Session), SourceFile(DiaSourceFile) {}
+DIAInjectedSource::DIAInjectedSource(CComPtr<IDiaInjectedSource> DiaSourceFile)
+    : SourceFile(DiaSourceFile) {}
 
 uint32_t DIAInjectedSource::getCrc32() const {
   DWORD Crc;