remove unused includes

This is to remove warnings from clangd.

Change-Id: Ic52dc864690cfacc437a99d5f42c0406492cef26
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/17580
Reviewed-by: Brett Wilson <brettw@google.com>
Commit-Queue: Takuto Ikuta <tikuta@google.com>

src/gn/ninja_generated_file_target_writer.cc

diff --git a/src/gn/ninja_generated_file_target_writer.cc b/src/gn/ninja_generated_file_target_writer.cc
index f09872e..307c12b 100644
--- a/src/gn/ninja_generated_file_target_writer.cc
+++ b/src/gn/ninja_generated_file_target_writer.cc
@@ -4,8 +4,6 @@
 
 #include "gn/ninja_generated_file_target_writer.h"
 
-#include "base/strings/string_util.h"
-#include "gn/deps_iterator.h"
 #include "gn/output_conversion.h"
 #include "gn/output_file.h"
 #include "gn/scheduler.h"

src/gn/target.h

diff --git a/src/gn/target.h b/src/gn/target.h
index b839277..5cf5360 100644
--- a/src/gn/target.h
+++ b/src/gn/target.h
@@ -17,7 +17,6 @@
 #include "gn/item.h"
 #include "gn/label_pattern.h"
 #include "gn/label_ptr.h"
-#include "gn/lib_file.h"
 #include "gn/metadata.h"
 #include "gn/output_file.h"
 #include "gn/pointer_set.h"