Use rmdir /s/q instead of flaky shutil.rmtree on Windows

build/clobber.py

Index: build/clobber.py
diff --git a/build/clobber.py b/build/clobber.py
index 785011a171d836f9cbf8dc0ddd101a015b3335de..264b390211e887107966c47d248cf7bfa6f5ea9a 100755
--- a/build/clobber.py
+++ b/build/clobber.py
@@ -7,7 +7,9 @@
 
 import argparse
 import os
+import platform
 import shutil
+import subprocess
 import sys
 
 
@@ -35,11 +37,20 @@ def extract_gn_build_commands(build_ninja_file):
   return result
 
 
+def delete_dir(build_dir):
+  # For unknown reasons (anti-virus?) rmtree of Chromium build directories
+  # often fails on Windows.
+  if platform.system() == 'Windows':

[scottmg, 2016/03/18 00:40:37]

I think "if sys.platform.startswith('win')" is more common. But if you have some
reason to do this, then that's fine. (If you switch, remove the import too.)

[brucedawson, 2016/03/18 20:55:50]

Ah - yes. That's what I was looking for. Done (including removing the import).

+    subprocess.call(['rmdir', '/s', '/q', build_dir], shell=True)

[scottmg, 2016/03/18 00:40:37]

.call -> .check_call

[brucedawson, 2016/03/18 20:55:50]

Done.

+  else:
+    shutil.rmtree(build_dir)
+
+
 def delete_build_dir(build_dir):
   # GN writes a build.ninja.d file. Note that not all GN builds have args.gn.
   build_ninja_d_file = os.path.join(build_dir, 'build.ninja.d')
   if not os.path.exists(build_ninja_d_file):
-    shutil.rmtree(build_dir)
+    delete_dir(build_dir)
     return
 
   # GN builds aren't automatically regenerated when you sync. To avoid
@@ -56,7 +67,7 @@ def delete_build_dir(build_dir):
   except IOError:
     args_contents = ''
 
-  shutil.rmtree(build_dir)
+  delete_dir(build_dir)
 
   # Put back the args file (if any).
   os.mkdir(build_dir)