[DebugInfo] Move several private headers to include directory

This patch moved the following files in lib/CodeGen/AsmPrinter/
  AsmPrinterHandler.h
  DbgEntityHistoryCalculator.h
  DebugHandlerBase.h
to include/llvm/CodeGen directory.

Such a change will enable Target to extend DebugHandlerBase
and emit Target specific debug info sections.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D55755

llvm-svn: 349564
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 56aac67..8a31e98 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -15,8 +15,6 @@
 #define LLVM_LIB_CODEGEN_ASMPRINTER_DWARFDEBUG_H
 
 #include "AddressPool.h"
-#include "DbgEntityHistoryCalculator.h"
-#include "DebugHandlerBase.h"
 #include "DebugLocStream.h"
 #include "DwarfFile.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -31,6 +29,8 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/Dwarf.h"
 #include "llvm/CodeGen/AccelTable.h"
+#include "llvm/CodeGen/DbgEntityHistoryCalculator.h"
+#include "llvm/CodeGen/DebugHandlerBase.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DebugLoc.h"