[PDB/CodeView] Rename some classes.

In preparation for introducing writing capabilities for each of
these classes, I would like to adopt a Foo / FooRef naming
convention, where Foo indicates that the class can manipulate and
serialize Foos, and FooRef indicates that it is an immutable view of
an existing Foo.  In other words, Foo is a writer and FooRef is a
reader.  This patch names some existing readers to conform to the
FooRef convention, while offering no functional change.

llvm-svn: 301810
diff --git a/llvm/tools/llvm-pdbdump/LLVMOutputStyle.cpp b/llvm/tools/llvm-pdbdump/LLVMOutputStyle.cpp
index 8ed1a90..eec0793 100644
--- a/llvm/tools/llvm-pdbdump/LLVMOutputStyle.cpp
+++ b/llvm/tools/llvm-pdbdump/LLVMOutputStyle.cpp
@@ -80,8 +80,6 @@
   BitVector UseAfterFreePages;
 };
 
-// Define a locally scoped visitor to print the different
-// substream types types.
 class C13RawVisitor : public C13DebugFragmentVisitor {
 public:
   C13RawVisitor(ScopedPrinter &P, PDBFile &F)
@@ -723,7 +721,7 @@
             File.getMsfLayout(), File.getMsfBuffer(),
             Modi.Info.getModuleStreamIndex());
 
-        ModuleDebugStream ModS(Modi.Info, std::move(ModStreamData));
+        ModuleDebugStreamRef ModS(Modi.Info, std::move(ModStreamData));
         if (auto EC = ModS.reload())
           return EC;
 
@@ -751,7 +749,6 @@
         if (opts::raw::DumpLineInfo) {
           ListScope SS(P, "LineInfo");
 
-          // Inlinee Line Type Indices refer to the IPI stream.
           C13RawVisitor V(P, File);
           if (auto EC = codeview::visitModuleDebugFragments(
                   ModS.linesAndChecksums(), V))