Modify build scripts for ios .framework to compile metal shaders.

webrtc/sdk/objc/compile_metal_lib.py

+# Copyright 2017 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+"""Compiles metal shader file into rtc_shaders.metallib.
+
+The produced metal library will be created in the output folder
+like so:
+  oututDir/rtc_shaders.metallib
+The script is intended to be used as gn action.
+"""
+
+
+import argparse
+import subprocess
+import sys
+
+
+def main():
+  parser = argparse.ArgumentParser(
+      description='A script to compile metal shaders.')
+  parser.add_argument('-i', '--input', required=True,
+                      help='Path to input metal shaders.')
+  parser.add_argument('-o', '--output', required=True,
+                      help='Path to output bundle.')
+  args, _ = parser.parse_known_args()
+
+ # TODO(denicija): replace the hardcoded iphoneos with
+ # the proper sdk var when we add metal for mac.
+  metal_air_args = [
+    'xcrun',
+    '-sdk',
+    'iphoneos',
+    'metal',
+    args.input,
+    '-o',
+    args.output+'/rtc_shaders.air'
+  ]
+  toolout = subprocess.Popen(metal_air_args)
+  if toolout.wait() == 0:
+    metal_lib_args = [
+      'xcrun',
+      '-sdk',
+      'iphoneos',
+      'metallib',
+      args.output+'/rtc_shaders.air',
+      '-o',
+      args.output+'/rtc_shaders.metallib'
+    ]
+    toolout = subprocess.Popen(metal_lib_args)
+    toolout.wait()
+
+  return toolout.returncode
+
+
+if __name__ == '__main__':
+  sys.exit(main())