Remove out/apprtc using Cygwin for Windows bots.

This requires Cygwin to be installed in c:\cygwin, which
is the case on all our Windows testers.

BUG=567538
R=phoglund@chromium.org

Review URL: https://codereview.chromium.org/1562343003 .
diff --git a/copy_apprtc.py b/copy_apprtc.py
index ca4750e..c0a6d5d 100755
--- a/copy_apprtc.py
+++ b/copy_apprtc.py
@@ -8,6 +8,7 @@
 import fileinput
 import os
 import shutil
+import subprocess
 import sys
 
 import utils
@@ -25,9 +26,23 @@
     sys.stdout.write(line)
 
 
+def RemoveDirectory(*path):
+  if utils.GetPlatform() == 'win':
+    # Allow clobbering of out dir using cygwin until crbug.com/567538 is fixed.
+    drive, path = os.path.splitdrive(os.path.abspath(path))
+    drive = drive.lower()[0]
+    cygwin_full_path = '/cygdrive/%s%s' % (drive, path.replace('\\', '/'))
+
+    # Now it should be like /cygdrive/c/b/build/slave/Win7_Tester/build/src/out
+    cmd = 'c:\\cygwin\\bin\\bash --login -c "rm -rf %s"' % cygwin_full_path
+    subprocess.check_call(cmd)
+  else:
+    utils.RemoveDirectory(path)
+
+
 def main():
   target_dir = os.path.join('src', 'out', 'apprtc')
-  utils.RemoveDirectory(target_dir)
+  RemoveDirectory(target_dir)
   shutil.copytree('apprtc',
                   target_dir, ignore=shutil.ignore_patterns('.svn', '.git'))