tools/gn: Remove includes of basictypes.h.

We can just use the standard integer types from stdint.h now that our
toolchain supports it and include macros.h for DISALLOW macros.

BUG=138542
TEST=gn and gn_unittests builds
[email protected]

Review URL: https://codereview.chromium.org/1280123005

Cr-Commit-Position: refs/heads/master@{#342570}
diff --git a/tools/gn/ninja_target_writer.h b/tools/gn/ninja_target_writer.h
index f67eba5..4598ae8 100644
--- a/tools/gn/ninja_target_writer.h
+++ b/tools/gn/ninja_target_writer.h
@@ -7,14 +7,14 @@
 
 #include <iosfwd>
 
-#include "base/basictypes.h"
+#include "base/macros.h"
 #include "tools/gn/path_output.h"
-#include "tools/gn/substitution_type.h"
 
 class FileTemplate;
 class OutputFile;
 class Settings;
 class Target;
+struct SubstitutionBits;
 
 // Generates one target's ".ninja" file. The toplevel "build.ninja" file is
 // generated by the NinjaBuildWriter.