Disable hashes for ANGLE features generator

Features autogen files are small, fast to regenerate.
Run the generator in --verify-only mode and check content every time,
instead of using hashes.

Bug: angleproject:8193
Change-Id: I3988ab50a6c33171b7b7252c03f34a74f09fcf18
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4604579
Commit-Queue: Roman Lavrov <romanl@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

scripts/run_code_generation.py

@@ -66,8 +66,6 @@ def auto_script(script):
 
 
 generators = {
-    'ANGLE features':
-        'include/platform/gen_features.py',
     'ANGLE format':
         'src/libANGLE/renderer/gen_angle_format_table.py',
     'ANGLE load functions table':
@@ -135,6 +133,12 @@ generators = {
 }
 
 
+# Fast and supports --verify-only without hashes.
+hashless_generators = {
+    'ANGLE features': 'include/platform/gen_features.py',
+}
+
+
 def md5(fname):
     hash_md5 = hashlib.md5()
     with open(fname, "r") as f:
@@ -252,8 +256,22 @@ def main():
     if not runningSingleGenerator and any_old_hash_missing(all_new_hashes, all_old_hashes):
         any_dirty = True
 
+    # Handle hashless_generators separately as these don't have hash maps.
+    hashless_generators_dirty = False
+    for name, script in sorted(hashless_generators.items()):
+        cmd = [get_executable_name(script), os.path.basename(script)]
+        rc = subprocess.call(cmd + ['--verify-only'], cwd=get_child_script_dirname(script))
+        if rc != 0:
+            print(name + ' generator dirty')
+            # Don't set any_dirty as we don't need git cl format in this case.
+            hashless_generators_dirty = True
+
+            if not args.verify_only:
+                print('Running ' + name + ' code generator')
+                subprocess.check_call(cmd, cwd=get_child_script_dirname(script))
+
     if args.verify_only:
-        sys.exit(any_dirty)
+        return int(any_dirty or hashless_generators_dirty)
 
     if any_dirty:
         args = ['git.bat'] if os.name == 'nt' else ['git']
@@ -273,6 +291,8 @@ def main():
                 json.dump(new_hashes, f, indent=2, sort_keys=True, separators=(',', ':\n    '))
                 f.write('\n')  # json.dump doesn't end with newline
 
+    return 0
+
 
 if __name__ == '__main__':
     sys.exit(main())