Remove the clang::SourceBuffer class, switch to the llvm::MemoryBuffer class.

llvm-svn: 39426
diff --git a/clang/Lex/Preprocessor.cpp b/clang/Lex/Preprocessor.cpp
index 7654d22..cbdb0ff 100644
--- a/clang/Lex/Preprocessor.cpp
+++ b/clang/Lex/Preprocessor.cpp
@@ -339,7 +339,7 @@
   if (MaxIncludeStackDepth < IncludeMacroStack.size())
     MaxIncludeStackDepth = IncludeMacroStack.size();
 
-  const SourceBuffer *Buffer = SourceMgr.getBuffer(FileID);
+  const MemoryBuffer *Buffer = SourceMgr.getBuffer(FileID);
   Lexer *TheLexer = new Lexer(Buffer, FileID, *this);
   if (isMainFile) TheLexer->setIsMainFile();
   EnterSourceFileWithLexer(TheLexer, CurDir);