[DebugInfo] Remove unnecessary <string> include dependency from DebugInfo headers. NFC.

At most these use the StringRef/Twine wrappers and don't have any implicit uses of std::string.

Move the include down to any cpp implementation where std::string is actually used.

include/llvm/DebugInfo/CodeView/CodeViewError.h

@@ -11,8 +11,6 @@
 
 #include "llvm/Support/Error.h"
 
-#include <string>
-
 namespace llvm {
 namespace codeview {
 enum class cv_error_code {

include/llvm/DebugInfo/GSYM/GsymCreator.h

@@ -12,7 +12,6 @@
 #include <functional>
 #include <memory>
 #include <mutex>
-#include <string>
 #include <thread>
 
 #include "llvm/ADT/ArrayRef.h"

include/llvm/DebugInfo/GSYM/GsymReader.h

@@ -9,7 +9,6 @@
 #ifndef LLVM_DEBUGINFO_GSYM_GSYMREADER_H
 #define LLVM_DEBUGINFO_GSYM_GSYMREADER_H
 
-
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/DebugInfo/GSYM/FileEntry.h"
 #include "llvm/DebugInfo/GSYM/FunctionInfo.h"
@@ -19,11 +18,9 @@
 #include "llvm/Support/DataExtractor.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/ErrorOr.h"
-
 #include <inttypes.h>
 #include <memory>
 #include <stdint.h>
-#include <string>
 #include <vector>
 
 namespace llvm {

include/llvm/DebugInfo/MSF/MSFError.h

@@ -11,8 +11,6 @@
 
 #include "llvm/Support/Error.h"
 
-#include <string>
-
 namespace llvm {
 namespace msf {
 enum class msf_error_code {

lib/DebugInfo/CodeView/CodeViewError.cpp

@@ -9,6 +9,7 @@
 #include "llvm/DebugInfo/CodeView/CodeViewError.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
+#include <string>
 
 using namespace llvm;
 using namespace llvm::codeview;

lib/DebugInfo/MSF/MSFError.cpp

@@ -9,6 +9,7 @@
 #include "llvm/DebugInfo/MSF/MSFError.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/ManagedStatic.h"
+#include <string>
 
 using namespace llvm;
 using namespace llvm::msf;