Revert r296215, "[PDB] General improvements to Stream library." and followings.

r296215, "[PDB] General improvements to Stream library."
r296217, "Disable BinaryStreamTest.StreamReaderObject temporarily."
r296220, "Re-enable BinaryStreamTest.StreamReaderObject."
r296244, "[PDB] Disable some tests that are breaking bots."
r296249, "Add static_cast to silence -Wc++11-narrowing."

std::errc::no_buffer_space should be used for OS-oriented errors for socket transmission.
(Seek discussions around llvm/xray.)

I could substitute s/no_buffer_space/others/g, but I revert whole them ATM.

Could we define and use LLVM errors there?

llvm-svn: 296258
diff --git a/llvm/lib/DebugInfo/PDB/Native/GSI.h b/llvm/lib/DebugInfo/PDB/Native/GSI.h
index f47321a..5c5596c 100644
--- a/llvm/lib/DebugInfo/PDB/Native/GSI.h
+++ b/llvm/lib/DebugInfo/PDB/Native/GSI.h
@@ -33,7 +33,9 @@
 
 namespace llvm {
 
-class BinaryStreamReader;
+namespace msf {
+class StreamReader;
+}
 
 namespace pdb {
 
@@ -54,14 +56,14 @@
   support::ulittle32_t NumBuckets;
 };
 
-Error readGSIHashBuckets(FixedStreamArray<support::ulittle32_t> &HashBuckets,
-                         const GSIHashHeader *HashHdr,
-                         BinaryStreamReader &Reader);
+Error readGSIHashBuckets(
+    msf::FixedStreamArray<support::ulittle32_t> &HashBuckets,
+    const GSIHashHeader *HashHdr, msf::StreamReader &Reader);
 Error readGSIHashHeader(const GSIHashHeader *&HashHdr,
-                        BinaryStreamReader &Reader);
-Error readGSIHashRecords(FixedStreamArray<PSHashRecord> &HashRecords,
+                        msf::StreamReader &Reader);
+Error readGSIHashRecords(msf::FixedStreamArray<PSHashRecord> &HashRecords,
                          const GSIHashHeader *HashHdr,
-                         BinaryStreamReader &Reader);
+                         msf::StreamReader &Reader);
 }
 }