Add optional verbose switch '-v' to build script. (#12118)

* Add optional verbose switch '-v' to build script.

* Remove tracer comment.

* Add --ninja-path switch.

For compatiblity with https://github.com/electron/electron/pull/12120

script/build.py

@@ -5,7 +5,8 @@ import os
 import subprocess
 import sys
 
-from lib.config import MIPS64EL_GCC, get_target_arch, build_env
+from lib.config import MIPS64EL_GCC, get_target_arch, build_env, \
+                       enable_verbose_mode, is_verbose_mode
 from lib.util import electron_gyp, import_vs_env
 
 
@@ -20,14 +21,25 @@ GCLIENT_DONE = os.path.join(SOURCE_ROOT, '.gclient_done')
 def main():
   os.chdir(SOURCE_ROOT)
 
+  args = parse_args()
+  if args.verbose:
+    enable_verbose_mode()
+
   # Update the VS build env.
   import_vs_env(get_target_arch())
 
-  ninja = os.path.join('vendor', 'depot_tools', 'ninja')
-  if sys.platform == 'win32':
-    ninja += '.exe'
+  # decide which ninja executable to use
+  ninja_path = args.ninja_path
+  if not ninja_path:
+    ninja_path = os.path.join('vendor', 'depot_tools', 'ninja')
+    if sys.platform == 'win32':
+      ninja_path += '.exe'
+
+  # decide how to invoke ninja
+  ninja = [ninja_path]
+  if is_verbose_mode():
+    ninja.append('-v')
 
-  args = parse_args()
   if args.libcc:
     if ('D' not in args.configuration
         or not os.path.exists(GCLIENT_DONE)
@@ -39,12 +51,12 @@ def main():
     script = os.path.join(LIBCC_SOURCE_ROOT, 'script', 'build')
     subprocess.check_call([sys.executable, script, '-D', '-t',
                            get_target_arch()])
-    subprocess.check_call([ninja, '-C', LIBCC_DIST_MAIN])
+    subprocess.check_call(ninja + ['-C', LIBCC_DIST_MAIN])
 
   env = build_env()
   for config in args.configuration:
     build_path = os.path.join('out', config[0])
-    ret = subprocess.call([ninja, '-C', build_path, args.target], env=env)
+    ret = subprocess.call(ninja + ['-C', build_path, args.target], env=env)
     if ret != 0:
       sys.exit(ret)
 
@@ -56,6 +68,10 @@ def parse_args():
                       nargs='+',
                       default=CONFIGURATIONS,
                       required=False)
+  parser.add_argument('-v', '--verbose',
+                      action='store_true',
+                      default=False,
+                      help='Verbose output')
   parser.add_argument('-t', '--target',
                       help='Build specified target',
                       default=electron_gyp()['project_name%'],
@@ -67,6 +83,9 @@ def parse_args():
                         '-d --debug_libchromiumcontent.'
                       ),
                       action='store_true', default=False)
+  parser.add_argument('--ninja-path',
+                      help='Path of ninja command to use.',
+                      required=False)
   return parser.parse_args()