Add --use-remoteexec to build_ios_libs.py

Similar to https://webrtc-review.googlesource.com/c/src/+/273600, this CL adds a flag for reclient build.

Bug: b/243628179
Change-Id: I48b2922a139ea05615073025c4c3ecc045482b46
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/273780
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Auto-Submit: Junji Watanabe <jwata@google.com>
Reviewed-by: Takuto Ikuta <tikuta@google.com>
Cr-Commit-Position: refs/heads/main@{#37978}
diff --git a/tools_webrtc/ios/build_ios_libs.py b/tools_webrtc/ios/build_ios_libs.py
index 01a95b0..093a002 100755
--- a/tools_webrtc/ios/build_ios_libs.py
+++ b/tools_webrtc/ios/build_ios_libs.py
@@ -95,6 +95,10 @@
                       action='store_true',
                       default=False,
                       help='Use goma to build.')
+  parser.add_argument('--use-remoteexec',
+                      action='store_true',
+                      default=False,
+                      help='Use RBE to build.')
   parser.add_argument(
       '--extra-gn-args',
       default=[],
@@ -149,7 +153,7 @@
 
 def BuildWebRTC(output_dir, target_environment, target_arch, flavor,
                 gn_target_name, ios_deployment_target, libvpx_build_vp9,
-                use_goma, extra_gn_args):
+                use_goma, use_remoteexec, extra_gn_args):
   gn_args = [
       'target_os="ios"',
       'ios_enable_code_signing=false',
@@ -176,6 +180,7 @@
 
   gn_args.append('use_lld=true')
   gn_args.append('use_goma=' + ('true' if use_goma else 'false'))
+  gn_args.append('use_remoteexec=' + ('true' if use_remoteexec else 'false'))
   gn_args.append('rtc_enable_objc_symbol_export=true')
 
   args_string = ' '.join(gn_args + extra_gn_args)
@@ -197,7 +202,7 @@
       output_dir,
       gn_target_name,
   ]
-  if use_goma:
+  if use_goma or use_remoteexec:
     cmd.extend(['-j', '200'])
   _RunCommand(cmd)
 
@@ -237,7 +242,7 @@
       lib_paths.append(lib_path)
       BuildWebRTC(lib_path, environment, arch, args.build_config,
                   gn_target_name, IOS_DEPLOYMENT_TARGET[environment],
-                  LIBVPX_BUILD_VP9, args.use_goma, gn_args)
+                  LIBVPX_BUILD_VP9, args.use_goma, args.use_remoteexec, gn_args)
     all_lib_paths.extend(lib_paths)
 
     # Combine the slices.